Sluggish acceleration in Low RPM's when cold, and no torq past 5k

[CJ_Boxster]

Hey My Peoples,

Ok after recieving my Boxster from the bodyshop, I immediatly noticed that the acceleration was lacking BIG TIME. So i figure since it wasnt drivin in 1 month I filled the tank up with gas and drove it abit and that seemed to clear up the low-mid RPM lack in power... However, the High RPMs (5k & Up) power curve seems to flat line.

Usually when that happens, I clean the MAF and problem solved but this time it didnt work, I also cleaned the airfilter and no change.

Yesterday morning I did notice that when the engine is cold, the mid-high rpm acceleration is non-existant until the engine warms up for about 30 seconds later, then the low - mid RPM power is there again... but still no power past 5k RPM's.

Anyone have any insite with this issue?

1997 2.5ltr 5-speed manual trans.

[1schoir]

Hey My Peoples,

Ok after recieving my Boxster from the bodyshop, I immediatly noticed that the acceleration was lacking BIG TIME. So i figure since it wasnt drivin in 1 month I filled the tank up with gas and drove it abit and that seemed to clear up the low-mid RPM lack in power... However, the High RPMs (5k & Up) power curve seems to flat line.

Usually when that happens, I clean the MAF and problem solved but this time it didnt work, I also cleaned the airfilter and no change.

Yesterday morning I did notice that when the engine is cold, the mid-high rpm acceleration is non-existant until the engine warms up for about 30 seconds later, then the low - mid RPM power is there again... but still no power past 5k RPM's.

Anyone have any insite with this issue?

1997 2.5ltr 5-speed manual trans.

Carlos:

The loss of power at 5K RPM's can be caused by a faulty MAF.

Are you getting any CEL's?

I had the same issue at 5K RPM's, among other issues on my '97 Boxster. I just replaced the MAF and will let you know if the 5K RPM loss of power has disappeared.

Regards, Maurice.

[rsfeller]

CJ,

I am NOT speaking from experience here but I think your answer may be in your comments. I've read on this board (and others) many times that there is only a certain point that MAF cleaning is effective before the intervals get short or non-existent.

It seems that most of use have mentioned flat power at approx. 5,000 rpm with MAF in need of cleaning and replacement.

My only other thought would be fuel filter age but my experience with other cars has been serious lack of power, bucking or deceleration if they truly get to the point of failure or clogging.

I'll be keeping my eye on this post because I know my MAF replacement days are coming soon!

[CJ_Boxster]

Hmm, well usually i would get about 2 months of trouble free acceleration out of every MAF cleaning... I do notice the occasional "Bucking" when deaccelerating from High RPMs to Mid RPMs.

I remember changing my Fuel Filter about a year & a half ago along with the fuel pump when I was having Bucking issues in the 1500-2000 rpm range 2 years ago and it Helped but didnt cure the problem and eventually the problem went away on its own but since I gotten the car back from Paint & Bodywork all these problems seem to have come back.

[1schoir]

Hmm, well usually i would get about 2 months of trouble free acceleration out of every MAF cleaning... I do notice the occasional "Bucking" when deaccelerating from High RPMs to Mid RPMs.

I remember changing my Fuel Filter about a year & a half ago along with the fuel pump when I was having Bucking issues in the 1500-2000 rpm range 2 years ago and it Helped but didnt cure the problem and eventually the problem went away on its own but since I gotten the car back from Paint & Bodywork all these problems seem to have come back.

CJ and Shawn:

Funny you should mention a fuel filter. I have one of those and I am planning to replace it as well. However, I am waiting until next week to do that so that I can pinpoint the "culprit", as it were.

I took the car out for a short drive (with the new MAF) and it definitely seems to be improved, both in terms of response and driveability (less hint of bucking, smoother acceleration). I will wind it out tomorrow and report back again.

BTW, I made the mistake of buying my previous MAF on eBay, and that is a definite no-no. Although it seemed to work fine at first, it only lasted about 3 or 4 K miles before throwing CEL's. I am guessing that it was not quite "new" and perhaps had been cleaned with MAF cleaner before being sent to me. The price was right, but the results were not ones I would like to experience again. I did clean the MAF once, and it got better for about two weeks, and then started throwing CEL's again.

The one I just installed was purchased from AutohausAz.com, they seemed to have the best price at the time (bought it back in January).

Regards, Maurice.

[CJ_Boxster]

Ah, Well at least its fixed Maurice.

I unplugged my MAF yesterday and took it for a drive and all the torq is back, so ill be looking for a new MAF now.

I also used my fathers very expensive ODBII scanner to see realtime values that the MAF is sending out to the cars computer and the air-temp was WAY off. It was 12 degrees C. outside and the MAF was telling the computer that the air temp is 45 degrees C.

[1schoir]

....

I am NOT speaking from experience here but I think your answer may be in your comments. I've read on this board (and others) many times that there is only a certain point that MAF cleaning is effective before the intervals get short or non-existent.

It seems that most of use have mentioned flat power at approx. 5,000 rpm with MAF in need of cleaning and replacement.

....

I'll be keeping my eye on this post because I know my MAF replacement days are coming soon!

Shawn & CJ:

Holy MAF, Batman!!!

After replacing my MAF this past weekend, yesterday was the first day I could really drive the car wide open. All I can say is that the difference is day and night!

The hesitation or flat spot that I would regularly get at about 5K RPM is COMPLETELY gone, and it pulls strong all the way to redline.

The driveability is also greatly improved and there is no more jerkiness when getting on it at low RPM's or on deceleration.

I have certainly learned a lot about certain CEL's over the past year, but I'd much rather be driving without those CEL's, which I constantly reset, but which would come back after various time periods despite cleaning what I thought was a brand new MAF. Sometimes one day, other times a few days, and still other times a month or even two. My Durametric sure got a workout. I am convinced that the MAF I bought on eBay was not new, despite being advertised as such.

The moral of the story: Do not buy an MAF from eBay. Get a new one from a reputable supplier (AutohausAz.com) in my case.

Regars, Maurice.

[CJ_Boxster]

Glad to hear that! Dont you just feel like driving it at the 5k plus RPM's more often when its working right :)

[1schoir]

Glad to hear that! Dont you just feel like driving it at the 5k plus RPM's more often when its working right :)

Not just often, but ALL THE TIME! :thumbup:

Regards, Maurice.

[rsfeller]

It's hard to believe the MAF has such a great impact on the value of the system but as far back as the 80s on my Vw Vans the temp2 (computerized water temp) and AMM (air mass meter) have huge impacts on the computer's decisions and they failed regularly. When either of these temp or air density sensors were bad there would be bucking and flat spots in the power band or a failure to hold idle and/or start.

Usually it was easy to figure out they were bad w/o having to put meters on them as simply unhooking them puts the car in a default or limp home mode. If the disconnection gives an a limited improvement you answer is usually there.

I make mention of this because CJ did the test of unplugging it and I would not of thought of this on a modern car!

I post this so others that find this tread can see that unplugging their MAF for testing will show show it's failure. Good job CJ...

...now when is my MAF going to fail?

I feel like I should just buy one now as it has to eventually happen to me! (70K miles). It's a shame the price on them hasn't drop considering how many aftermarket ones are needed by the public.

[1schoir]

It's hard to believe the MAF has such a great impact on the value of the system but as far back as the 80s on my Vw Vans the temp2 (computerized water temp) and AMM (air mass meter) have huge impacts on the computer's decisions and they failed regularly. When either of these temp or air density sensors were bad there would be bucking and flat spots in the power band or a failure to hold idle and/or start.

Usually it was easy to figure out they were bad w/o having to put meters on them as simply unhooking them puts the car in a default or limp home mode. If the disconnection gives an a limited improvement you answer is usually there.

I make mention of this because CJ did the test of unplugging it and I would not of thought of this on a modern car!

I post this so others that find this tread can see that unplugging their MAF for testing will show show it's failure. Good job CJ...

...now when is my MAF going to fail?

I feel like I should just buy one now as it has to eventually happen to me! (70K miles). It's a shame the price on them hasn't drop considering how many aftermarket ones are needed by the public.

Shawn:

Chris in NH has written up that test here a number of times. It's important not to forget to disconnect the battery for one minute so that the DME gets reset.

The price on the MAF sensors has even gone up recently. I don't know whether they attribute the increase to the weakening dollar or to something else, but I wouldn't be surprised if Bosch was manufacturing them in the U.S. :censored:

Regards, Maurice.

[panameras]

At what range of mileage does the MAF usually fail? During the last couple of weeks my 2000 Boxster S started to "hesitate" (not sure of the correct term to describe it) at around 1500-2000rpm, even when the engine has warmed up. I'm not sure if there are any changes at high rpms as I don't get much chance to use that rev range in traffic which is where I spend most of the time with the car. So after doing a bit of reading on here I assume it must be the MAF, either dirty or "failed"?

Bought the car at 38k miles, it has 45k miles on clock now and the last service was 2k miles ago. I have never cleaned the MAF before.

Does this sound like a MAF problem? Are there anything else I should look at?

Also what is a fair price for a new MAF?

Appreciate any help.

^^^Forgot to mention, car just had a new battery replacement 3 weeks ago.

[ericinboca]

At what range of mileage does the MAF usually fail? During the last couple of weeks my 2000 Boxster S started to "hesitate" (not sure of the correct term to describe it) at around 1500-2000rpm, even when the engine has warmed up. I'm not sure if there are any changes at high rpms as I don't get much chance to use that rev range in traffic which is where I spend most of the time with the car. So after doing a bit of reading on here I assume it must be the MAF, either dirty or "failed"?

Bought the car at 38k miles, it has 45k miles on clock now and the last service was 2k miles ago. I have never cleaned the MAF before.

Does this sound like a MAF problem? Are there anything else I should look at?

Also what is a fair price for a new MAF?

Appreciate any help.

^^^Forgot to mention, car just had a new battery replacement 3 weeks ago.

Don't know the life expectancy of a MAF, but Sunset just gave me a price of 271.45 for my 04 986S

[panameras]

Don't know the life expectancy of a MAF, but Sunset just gave me a price of 271.45 for my 04 986S

Ok thanks. :)

[JeTexas]

Body shops produce lots and lots of dust - just think of all the sanding and fiberglass cutting, etc. You don't think about that though since your car is all shiny and clean when you get it back.

I did some fiberglass work in my garage working on a Shelby replica, and everything is still completely coated in white powder.

All that dust and the MAF is a recipe for failure - especially if your car's been sitting in it for a month.

[geoff]

At what range of mileage does the MAF usually fail?

From personal experience on my '01 Boxster and what I've read here and on other forums, it's common for the original MAF to go out somewhere between 45K and 65K miles. Nothing scientific in my observation, just seems to be a regular occurrence. It's common to get a check engine light and P1128 and/or P1130 codes, then cleaning the MAF with contact cleaner makes the CEL go away. Lots of MAF information (but not expected life) at Mike Focke's MAF page.

I bought my replacement MAF (new OEM in Porsche box) from Sunset and was very happy with them (as always) - see link at top of each page, but a lot of people have said good things about AutohausAZ prices. Personally, I would never buy an MAF on eBay, since you never know what you will get or whether it will work.

[mrgylex]

Hmm, well usually i would get about 2 months of trouble free acceleration out of every MAF cleaning... I do notice the occasional "Bucking" when deaccelerating from High RPMs to Mid RPMs.

I remember changing my Fuel Filter about a year & a half ago along with the fuel pump when I was having Bucking issues in the 1500-2000 rpm range 2 years ago and it Helped but didnt cure the problem and eventually the problem went away on its own but since I gotten the car back from Paint & Bodywork all these problems seem to have come back.

Hi,

I am having issues with my car , it is not accelerating properly. I changed the MAF and cleaned the filter but still having weird acceleration. I will attempt the throttle body. the car has 80,000 miles and the fuel filter has not been changed, could that be a reason?..where is the fuel filter? is it easy to replace?

Thanks!,

Alex Flores

[1schoir]

Hi,

I am having issues with my car , it is not accelerating properly. I changed the MAF and cleaned the filter but still having weird acceleration. I will attempt the throttle body. the car has 80,000 miles and the fuel filter has not been changed, could that be a reason?..where is the fuel filter? is it easy to replace?

Thanks!,

Alex Flores

Alex:

IIRC, the recommended change interval is 60K miles, so you are overdue. A clogged filter will produce some of the symptoms you discovered.

The fuel filter is located under the car, just above the protective plastic underbody panels, just forward of the front of the engine. It's easy enough to replace once you get the car up.

Just be very careful with some of the fuel that can come squirting out under high pressure.

Regards, Maurice.