Hi all new to this forum... Thought I would try and see if you can figure this one out.

I have an 86 with 55K. It was sitting in storage for three years while I was stationed in Japan. Since reviving her last August, I have had some major issues lately. First, the water pump main seal started leaking severely. Got it fixed. Then the tranny was shifting really weird. A Trans filter solved that one. Then I had two fuel injectors stick wide open. So I had all of them replaced with the Accels from Corvette Central. Ever since I got my car back from that repair it has been running like crap!

When I start it up cold it seems to idle ok, maybe a little fast, but okay. When I start driving, she seems to hesitate initially but gets going. While I'm holding throttle open just enough to drive down the neighborhood I can feel a hesitation. Going down the highway, the hesitation (or coughing) is worse and more pronouced. When I go to WOT, it seems to not want to accelerate. Then once I'm at a stop, (I'm assuming in open loop at opetating temp, could have gotten them backwards) the car hunts for idle from 400-900 rpm's. The idle tends to divergently oscillate until it dies or I give it a little gas.

When the shop replaced the injectors, they also replaced the plugs, the O2 Sensor, the IAC valve, and the fuel pressure regulator diaphram, or so they say.

Any Ideas...

Anthony


[Modified by Twanster2000, 5:18 PM 7/3/2003]


[Modified by Twanster2000, 5:19 PM 7/3/2003]


[Modified by Twanster2000, 5:20 PM 7/3/2003]

 

A hunting idle is usually due to a faulty/dirty IAC or a vacuum leak. Check around under hood to assure there are no loose/broken vacuum hoses or loose connectors.

You can use the method on my site to see if the ECM is going & staying in closed loop. It may shed some light on the problem or at least eliminate some possibilities.

 

I thought a IAC problem too, but when I was trying to re-calibrate the idle, when I unplugged the IAC, it didn't seem to affect the car at all, it just idled a little lower. I also looked for vacuum lined that were broken/disconected and couldn't find any.

Any other suggestions?

 

similiar hesitation happen to my 89, i checked for codes and found Code32. replaced the egr switch fix it...

another problem was the fuel pump..when turning key, just before starting, listen for the fuel pump activation. should be able to hear it kick in. it should! check to see if you have the required pressure at the fuel rail (passenger side ,near the rear of the fuel rail is a connection)..use a gauge if you have one . 9 times out of 10 it is the fuel pump....... :cheers:

 

Replace fuel filter it haven't already. When good fuel goes bad it takes alot of things with it. Pump, filter and injectors.