Having a problem with my bone-stock 89 6-speed. Once the car gets warm, there is no throttle response. Anything more than very light pressure on the pedal, and it just idles. If shut-off, it will not restart until it cools back down. When cold, it will run fine at part throttle, but if you put your foot into it a little, it acts like a "hi-speed" miss. Fuel pressure at the rail is 30 psi, I changed the fuel filter, and the injector pulses look good. There are no codes, and everything looks fine on the scanner. I've read a few other posts and it seems that others have experienced this problem, but I haven't seen a solution.

Like I stated, the car starts fine when cold, and idles perfectly, so I don't think it's a vacuum leak issue. I've been chasing this for about a month and am at the end of my rope! Any advice would be appreciated.

 

I had a similar problem with my 93. It turned out to be the distributor. That was an LT-1, though. You should ahve an L-98, I thinjk. I would suggest you find a repair shop with an engine analyzer (Sun machine). They hook it up to the car and you should have your answer in no time flat. That's how I found out what my problem was after fighting the car and changing out perfectly good parts for over a year. Good Luck.

 

Try unplugging MAF. That will put it in a backup mode. See if throttle response improves any.