I have a 1989 IROC with the 305 TPI, (5 speed). The car normally runs great. However, it recently started having a problem when I first strat it up each morning, (or after it has sat for a few hours).

Upon inital start-up, it idles rough and irratically. It won't take the fuel and stumbles.

However, after it runs for just a couple of minutes, it runs great again. Idles correctly, takes the fuel well, and runs great.

If this were my old carburatored 1981, I would think the choke wasn't working. But fuel injection doesn't have a choke. I don't know much about the TPI.

Any idea what the problem might be?

Thanks in advance,
Danny

 

it could be a fuel injector leaking down and flooding the intake. i dont think 89 used a cold start injector. also, when was the last time it had a tune up? a cracked spark plug can do the exact same thing

 

It was tuned up about 4 months ago. It doesn't seem like one cylinder not fireing, (which a single injector would cause). It just won't take the fuel when you press the pedal. It stubmles and almost dies. It idles around 500 rpm's instead of the normal 1000 rpm's once it warms up. It also idles roughly for a moment.

 

you can have a leaking injector without a misfire. if it still works electrically, it wont misfire. i had the same issue with my dd (95 blazer) where the fuel injector assembly would bleed down when sitting. started up fine when cold, a bit sluggish hot, and took about 10 seconds of cranking if it sat for 2-8 hours. check it by hooking up a fuel pressure gauge and observing it over a period of time. also, does it use a maf or map?

 

It starts up fine with NO excessive cranking at all. It just runs sluggish, idles iratically, and won't take the fuel until it runs for a couple of minutes. It's not mising on one individual cylinder,...the fuel mix is just wrong when cold.

 

maybe you should re-read what ive posted. leaking injectors will cause that without a misfire. does the check engine light work, any codes? does it have a maf or map? 89 didnt have a cold start injector, so it wont be that. does it happen more when the engine is fully cold after sitting overnight, or at every start up?

 

The check engine light is off. I don't think it works. As I stated in my previous posts,...It ONLY does it when it's been sitting for several hours. It will start right up easily on first turn. However, it will not take the fuel when you press the gas pedal. It stumbles and tries to die. It idles roughly at around 500 rpm's. Once it runs for a minute or so, it clears up and runs perfectly.

It runs EXACTLY like my 81, (with a carb), when you disconnect the choke. Exactly the same.

I do not know what maf or map means.