Taking long time to start and Sputtering at idle. I need help!Pleeeease!

[LeeS97Z28]

Well, guys, I have a 1997 Z28 with 81K on the clock.Totally stock!

Here is a list of things that have been done.

New plugs and wires(Gm Ac Delco)dealer installed
New Optispark (Gm AcDelco) dealer installed
New EGR valve(Gm AcDelco)
New Water Pump(AcDelco)
New Intake Air Charge sensor
Cleaned the throttle body and put in new seals(AcDelco)
New Fuel Pump (AcDelco) Dealer installed yesterday

The Dealer said that the O2 sensors were okay. I know when I unhook both the front O2 sensors it still sputters.

Since I have a new fuel pump and it runs fine no misses from 1800 rpms to redline.
Do you guys think it could be fuel injectors.
If so what do you recommend!

[Bond Hawk]

Sounds like the Idle Air Control valve is either not working or sticking. Try replacing that to see if it solves your problem. It's connected to the throttle body.

http://shbox.com/1/iac3.jpg

[LeeS97Z28]

Thanks for your help I'll replace it.

Thanks Lee!

[Fastbird93]

What's the hard start condition like?? Is it a long crank time?? Sounds like it could be a leaky injector, have you checked for that??

[LeeS97Z28]

It takes four or five maybe six turns of the engine which didn't used to be but 1/2 to one turn. It also sputters but doesn't produce any black smoke!

Thanks Lee!

[Injuneer]

Has the dealer done a complete scan/diagnostic check? How do the long term fuel corrections look? Has the MAF performance been checked? Ditto on the TPS and the MAP sensors? These are all critical sensors. Hard starts can sometimes be traced back to a faulty coolant temp sensor. A good data log would show up many of these potential problems. Have they checked the air inlet bellows for a tear or being folded under the front edge of the throttle body? Have they checked for vacuum leaks?

Or has the dealer simply used the "replace a part and see if it helps" approach? That would be the typical Mr. Greedwrench approach

[LeeS97Z28]

The technician they let me talk two had the techII hooked up to the car and he said the O2 sensors were switching okay. I asked if they needed replacing he said No. He said even the misfire monitor showed no problems. But my car sputters which is a little miss so I know the misfire monitor show have shown which cylinder and how many counts.

Basically I have an Extended GM PP warranty good until june 29, 2004 and They have been replacing parts all I have been paying is the $100.00 deductible.

Thanks Lee!