My 2001 vette has had an intermittent start issue over the last few weeks (auto transmission, 50k miles). Previously, I have replaced the battery, starter, and ignition switch. I am confident in ruling out the battery and starter, but not the ignition switch.

Most the time, I am unable to go from the "off" position to start and have the engine crank. The DIC and all accessories work as normal. Most the time, I am able to go from the "on" or "acc" position to start and have have the engine turn over. The "off" position to start will work if I hold it there and wiggle the key in the cylinder. The TDR relay audibly clicks while actuating the key, there is no change with the shifter in park or neutral. I have also tested the resistance on the key and it is well in line with what it is supposed to be. I had swapped out the ignition switch roughly 9 months ago when the engine would randomly shut off while driving. Had no issues after, until this starting issue now.

I am at a loss as to what else could be the issue. Connections and grounds look fine elsewhere. My last idea is that the ignition switch is not making a proper connection, supported by the DIC voltage gauge dropping from time to time. No codes or other issues. If anyone has any insight, I'd appreciate some leads or ideas.

 

Moved to C5 Tech for recommendations.

 

If you can hear the TDR every single time you turn the key to the start position of the Ignition switch, it's not the Ignition switch. The next logical step is to replace the TDR.

 

If you have a DMM, are capable of using it, and can read schematics,.....the next step is to troubleshoot the problem in a hard fault state. Stop changing parts.

Also, post your codes: http://www.stengel.net/diccodes.htm