My poor old S2 starting misfiring out of no where, mostly in the lower revs. I did a tune up, map whack, cleaned the IAC??? crap and throttle body (as best I could) which has almost eliminated the problem but not completely. The check engine light is on and has been for a while but that is for code po411 (secondary air crap) but nothing else is coming up. Its an infrequent problem but when at idle you can hear a miss every so often and when accelerating it breaks up like a dead cylinder up till almost 2k rpm then goes good. It only does this sometimes, no pattern aside from it being at low revs. Any ideas??

 

check all of your coils

 

I went to the mechanic yesterday and we could not find anything wrong or out of place, car actually was running like a champ. Right now the mechanic is thinking I may have had a tank or 2 of bad gas. I went to a different gas station to fill up and I will see how it goes over the next couple of days. I did get roll center adjusters and adjustable camber ball joints in yesterday while I was there so I'm happy right now.

 

If the problem returns check your spark plugs for fouling (wet). Change/clean plugs and replace secondary air pump. Or get a secondary pump delete kit. When you start the car it's rich and the secondary provides some air to reduce emissions. After start the pump turns off and the ECU leans the mixture so it now "runs like a champ". Keep us posted.

Utah

 

Thanx for the input, I actually did purchase the delete kit and just got it in the mail, plan on working on it tomorrow. I'll keep this thread going in hopes if any 1 else runs across a similar issue we can all bring it to a close