Hi Everyone, Love the forum and all the information!

I have a 1996 base model C4 with 62,000 miles. Last week I took the vette out to run some errands. The car had been sitting in the garage for about a week before this trip and had a full tank of gas. I drove about 30 miles to my first errand turned off the car and it sat for about 10 minutes. Started it up with no issue.

Drove it another 20 miles to second appointment and it sat in the parking lot for about an hour. Started the car and it started running rough and only after applying a bit of gas did the problem go away.

Drove another 35 miles to next errand and the car sat for about 45 minutes. When started it ran very rough and I again applied some gas and it seemed to run better.

After this I ran the engine RPMs up to see if that would help and the rough starting issue has not happened again. Although at idle at a stop light the engine does not seem to be running as smoothly as before and there seems to be a new vibration from the engine at a timed interval (trying to explain as best as I can in writing). But it will idle without having to raise the RPMs.

So I am wondering how one would know if a fuel injector is going bad? Or could this be something else?

I bought the car back in April and the previous owner owned the car for 10 years and only put 9K miles on it. When I purchased the car it had 56K miles and has been running well until this little issue. I am learning about the LT1 engines but this issue has me a bit perplexed.

Appreciate the thoughts.

 

I would put a fuel pressure gauge on it and tape it to the winshield and see what it does. and see how long it holds after shutting off. also pull the vacumme line off the fpr and smell for fuel. once it is dark look for arcking and sparking by the plugs a mist of water will help. do not get the opti wet

 

Thanks Antfarmer2. I'll give this suggestions a try this weekend and see what I can find.

 

I have a 1996 and also the Factory Service Manual on CD (I was able to copy it to a flashdrive to speed up use). Unfortunately I cannot copy any of the information from the manual to paste into a response or Word using Adobe as it is password protected.

I suggest you get a copy. You can get a paper copy or a CD from Bishko on Ebay. Here is a link to the CD on Ebay -
http://www.ebay.com/itm/1996-Chevrol...xWakuT&vxp=mtr

If you get the paper version, make sure you get the red cover two volume edition. Do not get the white cover edition as it is a preliminary edition not the final edition. The paper edition is more expensive than the CD and some people prefer it. However, once I got use to using Adobe to read and search it, I think I now actually prefer it to a paper manual.

Starting on page 6-616, the manual has a diagnostic method for diagnosing hard starting and other problems. Preliminarily, check all electrical connections especially at the PCM, PCM grounds, vacuum lines, coil connections, fuel pressure and FPR (pull the vacuum line off the FPR and check for fuel), and vacuum venting system for the distributor for restriction, ignition wires for cracking, coolant temperature sensor, vacuum leaks at intake and MAF. Also check for stored DTC codes in the OBDII system - if you don't have a code reader, get one as it will be a good help now and in the future.

Good luck in tracking it down.

 

I would definitely check the vacuum line for the FPR for any fuel or wetness in it. A simple thing to check and a leading cause of hard starting and similar symptoms.

If that all looks good I would consider the ICM as a possible problem.

I would also check the plug wires for any sparking especially near the water pump (coil wire). Obviously do it in darkness.