Please Help me with Surging Problem
 

I have a 89 911 3.2.
500 miles ago had valves adjusted , new plugs and air filter changed .
Car starts up cold or warm everytime . However In the last month after driving around 20 - 30 miles then stopping for about a half hour , the car surges at idle only . This lasts for about 30 seconds and then back to normal. If I race the engine it goes back to normal instantly . It does not surge all the time . If not for this the car runs strong .

Help Please



What are your thoughts
Thanks ,
Vinnie from ventura
89 Silver Anniversary 911

Too rich or base idle set too high will make my 86 3.2 surge.

Joe

Yep, you can back out the bypass screw on the airflow meter to lean out the idle if that's the problem.

Common problem. When I had it, Tyson and the guys at TRE dialed-in the mixture. It's been rock-solid ever since.

My Wrench is telling me that it might be my O2 sensor .
Any Thoughts on this one

Thanks ,
Vinnie in Ventura

Before I had the mixture adjusted, I replaced the O2 sensor, the head temp sensor, and the idle control valve. Nothing helped until the mixture was adjusted. Sometimes the simplest solutions are the best.

But, if your car has more than 60k (?) on it, and the O2 sensor has not been replaced, it's not a bad idea to replace it anyway. It's a do-able DIY job. Our host sells the OEM sensor, and you can also buy a generic Bosch sensor and splice your old wiring harness on to it. I did the latter, and saved about $75 or $100.

Could be..When was the last time the 02 sensor was changed?

Could also be the ICV sticking a bit. I'd clean it out with some carb cleaner...Probably take you 10 minutes.

Thanks ,
love a ride in the Bell .
My Partner in Business flies a 410 Cessna,( Real Sweet )

Surging problem fixed .
Wrench told me to put in Redline gas treatment and drive .
He was right, injector was dirty , cleaned out , runs great !!


Vinnie in Ventura
89 Silver Anniversary 3.2 L

My 86 was having trouble at idle. I had a local wrench set the mixture. It didn't fix it.

I found (when I pulled the engine)that the #5 intake was loose enough that I could remove the bolts by hand. After I tightened those I have never had an idle problem again. The local wrench told me he checked that intake and it was tight. Thats why I will never trust this mechanic.