My '89 RS 305 TBI automatic has three issues that I hope are related; looking for advice in case my first fix doesn't work.

1) It runs great, and as long as I drive like there's a egg under my right foot I have no problems. BUT - if I stomp on it (which I only do when I have to ), it bucks and snorts and acts like it's about to come apart. Not real safe...

2) If it sits for between 20 minutes and an hour-and-a-half after it's warmed up it will start, then die. I have to feather the accelerator until I can get it to rev to about 4K, then it runs fine.

3) On cold days (below about 40F), it backfires on first start of the day. It won't do that for the rest of the day.

No SES light.

Almost 200K miles; I'm replacing the throttle position sensor in the next few days. What else should I check while I'm at it?

I would definately check your timing. It sounds like timing, and its free to check

Yeah, I'd definitely check your timing to start. Make sure your timing hasn't jumped.

i had a problem almost exactly like this last week with a 2.8 and it turns out the cat was clogged to the point it was glowing red.

Will check timing! Now why didn't I think of that - duh...

I'll put the catalytic converter on the list, too! Thanks!

Just disconnect the cat right there where it connects to the Y-pipe if you can. run the car. If it runs well, that's probably your problem.