Strange hestitation, no fault codes

[russhearl76]

Hi everyone, I'm new to the forum. Very impressive collection of users, post and knowledge!

Anyways, I have a 03 996TT that now has 53k miles. I've owned the car since 18k miles (about 2.5 years) and I've had the same problem since day one. The problem is that when I change gears and start to give it a little gas that the engine suddenly stumbles for a fraction of a second. The oil pressure guage drops quickly and then resumes its regular pressure reading. The same stumble happens when I let off the gas while in the same gear and then begin to slowing accelerate again... the engine stumbles, oil pressure drops quickly and then recovers.

I've taken the car to several dealers who have not been able to figure it out - perhaps because the computer isn't throwing off any fault codes - and without codes they are too lazy to diagnose the problem.

The problem is really annoying because its feels like a bucking bronco - just not smooth acceleration at all. Since there are no error codes, I can't seem to find anyone that can figure out what is going on.

Has anyone experienced this problem and does anyone know what the issue could be?????

Thank you!

Russ

[wross996TT]

:welcome: Russ,

Can you give some more info? What rpm does this happen? Changing between what gears? When was the last plug change? What plugs are your running? Have you checked the coil packs? Any mods? Sounds a little like variocam stutter which is normal...you just need to stay on it as you shift...

Edited September 3, 2009 by wross996TT

[russhearl76]

:welcome: Russ,

Can you give some more info? What rpm does this happen? Changing between what gears? When was the last plug change? What plugs are your running? Have you checked the coil packs? Any mods? Sounds a little like variocam stutter which is normal...you just need to stay on it as you shift...

Thanks for the welcome! Truth be told, I've been lurking for quite a while. I wish I could contribute knowledge like I could when I was building and racing TT Supras. Anyhow, the stutter I'm experiencing happens generally at lower RPMs and occurs when I change between all gears. It's like I shift into gear, start to apply the throttle, and then, bam, the engine feels like it cuts out for a half-second and then it recovers. A corresponding oil pressure drop (judging by the guage) occurs at the same time.

I'm running the factory spec plugs - they were replaced 15k miles ago. I haven't checked the coil packs and I don't have any mods. I've heard about the variocam stutter, but this reminds me of a faulty distributor that couldn't distribute the electricity properly and caused the engine to hesitate. I know this car uses coil packs, so I'm using this illustration as an example in case anyone knows the type of stumble I'm talking about.

Russ

[wross996TT]

how's your clutch?

[dg930]

Hi everyone, I'm new to the forum. Very impressive collection of users, post and knowledge!

Anyways, I have a 03 996TT that now has 53k miles. I've owned the car since 18k miles (about 2.5 years) and I've had the same problem since day one. The problem is that when I change gears and start to give it a little gas that the engine suddenly stumbles for a fraction of a second. The oil pressure guage drops quickly and then resumes its regular pressure reading. The same stumble happens when I let off the gas while in the same gear and then begin to slowing accelerate again... the engine stumbles, oil pressure drops quickly and then recovers.

I've taken the car to several dealers who have not been able to figure it out - perhaps because the computer isn't throwing off any fault codes - and without codes they are too lazy to diagnose the problem.

The problem is really annoying because its feels like a bucking bronco - just not smooth acceleration at all. Since there are no error codes, I can't seem to find anyone that can figure out what is going on.

Has anyone experienced this problem and does anyone know what the issue could be?????

Thank you!

Russ,

Russ

I have been dealing with what seems to be a nearly identical problem with my 2001 TT. So far I have a long list of what isn't wrong. I don't want to hijack your post with the details of my problem and all the stuff I've tried to do to fix it.

The only thing that the most recent shop has found as an anomaly (no answer yet if this could cause the hesitation) is a 1 degree variation in cam angle between the cams. Send me a PM with your number if you want to compare notes. I'll post the details here if you want too,

Dave

[D_Nyholm]

I too have the same symptoms on my 01 996TT. IT seems right at 1500 prm the car stumbles for a second. From reading around, it sounds like the variocam but I am not certain that is all it is. At one time, the car shook so violently that it seemed like it stalled, it was complete off and then on again. I am going to change the plugs and coils this winter and see if that helps since I don't believe my coils were changed, but I know the plugs were less than 10K ago.

[willmac996]

I too have the same symptoms on my 01 996TT. IT seems right at 1500 prm the car stumbles for a second. From reading around, it sounds like the variocam but I am not certain that is all it is. At one time, the car shook so violently that it seemed like it stalled, it was complete off and then on again. I am going to change the plugs and coils this winter and see if that helps since I don't believe my coils were changed, but I know the plugs were less than 10K ago.

Hi Gents,

Sorry to ressurect this thread, however I have exactly the same fault with my 2003 model 996t.

At pretty much exactly 1500 rpm, the car hesitates ( sometimes minimal, sometimes more pronounced )

Have not noticed this at any other RPM. It appears to be worse in first gear than any of the others. The previous owner had it back to OPC and they found no fault codes, so as is often the case they dismissed it as Variocam. However, I have read so many similar issues with this , it is more than evident that there is a fault.

It is unfortunately tarnishing my enjoyment of the car, as when it hesitates you can see people looking at you as if you cannot drive and it becomes annoying.

The car is standard with no mods, has done 47000 miles and has been serviced very regulary.I have not tried to replace any parts associated with what was causing this. A few people have suggested trying a new MAF, which I will do when i get home ( unfortunately work away from home a lot ). But the main thing is the car is still under warranty, so I really am keen to find out what is causing it so I can make sure OPC get it fixed and not fob me off with any more excuses.

I would really appreciate any input regarding this as I know someone must have gotten to the bottom of what seems to be a fairly common problem.

many thanks

Willie

[Sunnyside]

Does anybody know if the OP fixed the problem. Why hasn't he given an update. Its like reading a novel to find the last chapter missing from the book :(

This is not the first time this sort of engine problem has occurred , it would be nice to nail a solution to it for future reference

Frank

[lazysurf]

Hi,

Just to add another one to the list, but I experience the same problem on my '02 TT. It's a tiptronic, 63k miles, no mods, and seems to hesitate at about 1500 rpm under light acceleration. Not noticed it under heavy acceleration as I'm never down in that rev range. My car's been serviced on schedule. I've not asked any OPC or Indy to look at it yet.

I cleaned my MAF last weekend as the first starting point. Which hasn't changed anything. Will be having a go at cleaning my throttle body soon.

Would be interested in any other ideas people might have.

Cheers,

Doug

[PAULUNM]

On another board, Kevin recommended plugs, coils, and REPLACING MAF- not cleaning.

If anyone's had any luck with this- please chime in.

[willmac996]

Hi All,

Just to update you on hesitation at 1500 rpm. I have had car in OPC last few days to check out this issue, and they have come back and told me that it was loose intercooler pipework.

I have not got car back yet to try it, as unfortunately the heavy clutch pedal that I have been getting checked at same time has been diagnosed as requiring a new clutch !!

However they assure me that the hesitation has been cured. Will update further once I get car back but may give you all some ideas where to start for now rather than changing coil pack / plugs / MAF.

Cheers

[fdorn]

I have an 01 with 70k miles. I have noticed this same issue between 1700-2000 rpms. No faults. It seems to happen more often when the car is cold. It doesn't happen all the time. Plugs, coils, new MAF did not fix my problem.

willmac996 - can you please provide more detail on what 'loose intercooler pipework' means when you have it.

Edited November 22, 2010 by fdorn

[skymast]

OK. I have this EXACT same problem on an 02 with about the same miles or about the same time frame. What i have noticed is that this problem typically happens after I fill the car up with gas. Also, it did it before and after I change the spark plugs.

The bucking that you describes happens basically at lower RPMs when i am driving away from a dead stop and through 1 - 2 - 3 gears ... almost like its fuel starved. after a few really annoying minutes it stops and runs pretty well.

Mark

Hi everyone, I'm new to the forum. Very impressive collection of users, post and knowledge!

Anyways, I have a 03 996TT that now has 53k miles. I've owned the car since 18k miles (about 2.5 years) and I've had the same problem since day one. The problem is that when I change gears and start to give it a little gas that the engine suddenly stumbles for a fraction of a second. The oil pressure guage drops quickly and then resumes its regular pressure reading. The same stumble happens when I let off the gas while in the same gear and then begin to slowing accelerate again... the engine stumbles, oil pressure drops quickly and then recovers.

I've taken the car to several dealers who have not been able to figure it out - perhaps because the computer isn't throwing off any fault codes - and without codes they are too lazy to diagnose the problem.

The problem is really annoying because its feels like a bucking bronco - just not smooth acceleration at all. Since there are no error codes, I can't seem to find anyone that can figure out what is going on.

Has anyone experienced this problem and does anyone know what the issue could be?????

Thank you!

Russ

Edited November 23, 2010 by skymast

[willmac996]

OK gents, just to update you:

I had the car into OPC to have new clutch fitted and also look at the hesitation problem.

As already mentioned it was occurring at pretty much bang on 1500 RPM. It was most noticeable in 1st gear, and could be a quite savage hesitation sometimes , and slightly less noticeable at other times. It also occurred in 2nd and 3rd gears at times , but was not as savage.

Initially OPC stated that it was not an issue as all Turbo's have this hesitation and it was down to the Variocam. I knew this was "Bull" so persevered with them.

They then reported that they had found the problem and it was a loose intercooler hose , however when I later to spoke to the Service manager he informed it was actually a loose Turbo pipe. After getting the car back , it was a different beast. The hesitation had gone and it was smooth to drive for the first time, and I was grinning from ear to ear. However, I have since covered around a 1000 miles and I have noticed a very slight hesitation again at around 1500 RPM , but it is very very slight.

The car has been back into OPC since to replace an idler pulley ( bad bearing ) and I asked them to again check for the hesitation. They say they have checked the tightness of all intercooler hoses , run diagnostics and have come up with no problems. I have also replaced the MAF with a new item myself just to be on the safe side. But there is still a very slight hesitation. I know there must be something else causing this , and it may take some time to get to the bottom of it, however compared to the way it was I can certainly live with it for the foreseeable future.

Appreciate if anyone else has any input to try and find another possible cause. But maybe what I have mentioned so far may help some of you to start some fault finding.

[fdorn]

Thank a million for posting this -

OK gents, just to update you:

I had the car into OPC to have new clutch fitted and also look at the hesitation problem.

As already mentioned it was occurring at pretty much bang on 1500 RPM. It was most noticeable in 1st gear, and could be a quite savage hesitation sometimes , and slightly less noticeable at other times. It also occurred in 2nd and 3rd gears at times , but was not as savage.

Initially OPC stated that it was not an issue as all Turbo's have this hesitation and it was down to the Variocam. I knew this was "Bull" so persevered with them.

They then reported that they had found the problem and it was a loose intercooler hose , however when I later to spoke to the Service manager he informed it was actually a loose Turbo pipe. After getting the car back , it was a different beast. The hesitation had gone and it was smooth to drive for the first time, and I was grinning from ear to ear. However, I have since covered around a 1000 miles and I have noticed a very slight hesitation again at around 1500 RPM , but it is very very slight.

The car has been back into OPC since to replace an idler pulley ( bad bearing ) and I asked them to again check for the hesitation. They say they have checked the tightness of all intercooler hoses , run diagnostics and have come up with no problems. I have also replaced the MAF with a new item myself just to be on the safe side. But there is still a very slight hesitation. I know there must be something else causing this , and it may take some time to get to the bottom of it, however compared to the way it was I can certainly live with it for the foreseeable future.

Appreciate if anyone else has any input to try and find another possible cause. But maybe what I have mentioned so far may help some of you to start some fault finding.

[PAULUNM]

I was hoping Loren would chime in here- Loren, what are your thoughts on this issue?

[Loren]

Please have a look at look at these two threads...

[porsche996tt_tpe]

I bought a 2002 TT with 50K KM on it. I noticed this hesitation at low RPM. Since I had no prior experience to compare it with, I assumed this was normal. A couple of months later, the engine warning light came up and I had the MAF replaced. It's been a couple of months now and had not noticed this problem since the MAF replacement or it became very slight, it didn't bother me...

[fedmax]

I had the same issue as described and at first I thought its the MAF, replaced it same issue again. It was one broken variocam mounting bracket as described in lorens post. My porsche dealer said that they replace the two brackets at the 120'000km spark plug service as they're known to break.

[PAULUNM]

I had the same issue as described and at first I thought its the MAF, replaced it same issue again. It was one broken variocam mounting bracket as described in lorens post. My porsche dealer said that they replace the two brackets at the 120'000km spark plug service as they're known to break.

Can anyone tell me what the part number is for the variocam bracket?

Thanks!

[Loren]

I had the same issue as described and at first I thought its the MAF, replaced it same issue again. It was one broken variocam mounting bracket as described in lorens post. My porsche dealer said that they replace the two brackets at the 120'000km spark plug service as they're known to break.

Can anyone tell me what the part number is for the variocam bracket?

Thanks!

996.105.310.72 Support bracket -- US MSRP $18.52 each