Hey guys. I have a 1986 Trans Am with the 305 TPI engine. It sat for a few years before i bought it (last July) I have it running to the point where it can drive but I have some issues with it running. First off, it usually hesitates when i start it. By this i mean it cranks starts and revs and drops to like 200 rpm for a few seconds then jumps back to normal. It sounds like it runs very rough, like its missing or the timing is off. it idles normal. If you mash the pedal to the floor it bogs severely. Like it is barely running. if you feather it you can usually get it to climb to redline just fine. This issue is on and off. i never know when it will happen. It does this even under load driving. It also backfires out of the intake when you mash the pedal. I have replaced all 8 spark plugs, whole distributer, cap and rotor. I pulled the engine codes and code 33 comes up (MAF sensor) sensor is fine (wires not broken etc) checked vac hoses etc. Im thinking it could be a timing issue because it is backfiring but im not sure. Any help would be greatly apreciated. Thanks. Here is my video of the issue below

http://www.youtube.com/watch?v=A8Fbu...ature=youtu.be

 

Stumble and hesitation on throttle tip-in can be a lean mixture problem, just as backfire can be a lean issue.

The 33 DTC is usually caused by an over-reporting MAF, and can be related to a misadjusted TPS.

The video you posted seems to indicate a decent idle quality.

 

Thanks for the response. Is there a way i can check the TPS or adjust it?

 

I had this exact issue in my 89 Iroc I bought last February. For me, it turned out I had an overworked fuel pump and rust in my lines causing blockages. While troubleshooting this I also found I had a few bad injectors contributing as well.

 

I had an intermittent TPS failure on a different car, did the same thing, the ONLY way I figured that out was running my datalogger, and I could see everytime it would bog and backfire, that my TPS went offline. It was only every now and then. So it was hard to diagnose.

Your car sat for a long time, hows the fuel? Fuel filter? Air filter? Top that thing off with some premium, and do the seafoam treatment then run it or a while. Sitting that long does bad things to a car.

 

Oh, and the MAF sensor can appear fine, but like any electrical part, it can be bad without visually looking bad. You can clean the MAF sensor with electric parts cleaner.