running rough at idle

[karlooz]

i am experiencing a rough idle when warm. when cold, it runs smoother but think its due to the slightly higher idle rpm. claridge's diagnosed/guessed it was the MAF. i had it replaced but it still runs rough. could it be the o2 sensors, clogged injectors, carbon build up? would a bottle of techron help?

oh btw, they replaced the gas cap under the recall and now my CEL is on. the CEL was off before the recall "fix". funny, huh? :cursing:.

tia

c

Edited January 26, 2004 by karlooz

[Loren]

could it be the o2 sensors, clogged injectors, carbon build up?

Yes, yes, and yes.

would a bottle of techron help?

Wouldn't hurt. I run a bottle through about every 3000 miles or so.

Your MY99 C2 is not e-gas - you have a conventional throttle cable and linkage. I would remove the air cleaner intake and have a look at the throttle body and butterfly. These tend to carbon up and I use spray Gumout or Gumout on a lint free rag to clean them.

Further diagnosis would like require a scanner and or scope to see if one cylinder is causing the problem. If it is one cylinder then it could be a stuck or leaky injector or even a bad spark plug. I have even seen rough idle caused by a cracked oil separator so more investigation is needed.

If your CEL is on then you have a problem - usually emissions related. Could be as simple as the gas cap or oil filler cap, or it could be part of your rough idle problem. There should be a P-Code for the CEL cause that may give a hint to your rough idle problems.

[karlooz]

thx loren,

time to get me a OBDII scanner.

[vjd3]

My 99 runs rough at idle too, but the dealer says it's not throwing any codes and it feels "normal" to them. Feels rough to me. Anything else to check here?

Vic

99 C2 cab

[Loren]

My 99 runs rough at idle too, but the dealer says it's not throwing any codes and it feels "normal" to them. Feels rough to me. Anything else to check here?

Vic

99 C2 cab

Fuel filter, spark plugs, water in gas?

Could be lots of things. Best to just start eliminating variables.

[SFBayArea Jimmy]

My 99 runs rough at idle too, but the dealer says it's not throwing any codes and it feels "normal" to them. Feels rough to me. Anything else to check here?

Vic

99 C2 cab

Hi Vic, if your dealer gave your baby the clean bill of health, I won't worry too much. I would try a bottle of Techron in a full tank of Chevron gas just BEFORE your next oil change and please give us a update. :cheers: