Hey guys! I have an 89 vette and when it gets hot, it has troble starting and if it starts poorly, it idles like s**t! I goes as low as 400rpm and struggles to stay started. This tend to only happen when the car is hot, but the bad starting randomly happens. The car only had 80,000 miles ( Just clocked over today ) and has new injectors ( 3 months old ). Any ideas would be great!!! Thanks guys!

imb1987

 

It could be quite a few things but if I had to guess I would start with the ignition module. It's easily removed and can be bench tested at most auto parts stores. I know Advance Auto can test them. Modules tend to fail hot so make sure it gets tested 4-5 times in a row. I've seen them pass the first 3-4 times then fail.

 

You first need to look at TPS voltage (Throttle Psisition Sensor), make sure signal is around a half a volt and steady. Also, idle control motor might be sticking, but to be sure I would half to look at what is called cross counts which you would have to have a scanner for. Then check for any troubler codes. Some othe things to check could be EGR, fuel pressure (regulator could be sticking driving pressure to high), Mass Air Flow. It will be awfully difficult without a scan tool, though.