HI!

I've searched the forums and I see that this is a common issue, but I haven't seen any resolutions. When I first crank my 89, it runs great. I can floor it, and it will perform exactly like you want. After about 10 mins of around town/very slight highway driving (like 2 miles), It starts to want to bog. I press the gas, and it sputters and actually starts to slow down. It even does this in park. If I leave it for about an hour, it will perform flawlessly. Any ideas? I hope you guys can help me out. I just wanna start driving!!!

~Drew

 

First step is change fuel filter.

 

Ok. Changed the fuel filter, cleaned TB, pulled and cleaned TPS and IAC, replaced CTS. Ran great for about 10 mins until it heated up, then stumbled non stop. Even died a couple times. What else could be making it do this? It's only when hot. If I let it sit, it'll be fine until it gets hit again.

 

Anyone? Bueller? Bueller?

 

Might be a long shot, but have you checked to make sure the knock sensor is connected? I had a similar sounding issue with my GTA years ago. Baffled the hell out of me. Then I noticed the knock sensor wire had come off the sensor. After reconnecting it and making sure it wasn't loose, the car ran fine.

 

Vacuum leaks?

Fuel pressure?

Fuel pressure regulator diaphragm leak?

MAF or MAP operating properly?

That should keep you busy.

 

OK so I finally got it throw a SES light. Got codes 34 and 44. I bought a new MAP and am going to put it on tonight when I get off work. Hopefully this solves the problem!

 

Well? did it work? did you check the knock sensor? i think mine is off too i'm going to look tonight.

 

I know that a bad coil will cause the symptoms you described when the car gets up to operating temp. If the new MAP didn't work I would bench test your coil.

 

This is where it's good to be able log data or at least view the operational data with a scanner.

My suspicion is your fine running in open loop (when the ECM is ignoring the O2 sensor), but when you get up to operating temperature and into closed loop, the ECM is reacting to something that the O2 sensor is reacting to and pulling fuel out. In which case, it's something on the side of the engine that the O2 sensor is on.

 

never discount the possibility of a partially clogged cat or fully soot filled muffler

 

Code 44 is O2 sensor lean, likely due to a failing fuel pump...

RBob.