I recently purchased a 1986 corvette 4+3 with 79k. When I purchased it, it would go into limp mode if I accelerated hard. I could ease into the throttle and it would run great. I initially thought it was ECM issues or prom because I had ECM DTC codes. So I replaced the ECM and had no change. Thanks to search function I narrowed that down to maf sensor relays. I Replaced one then the other and car ran great for about 20 miles. Then it suddenly starts chugging or cutting out at around 2k rpm. I have also had problems starting from time to time. Everything inside is lit up but when I turn the key it's got nothing. I unhook the battery and hook back up after 10 seconds and it fires right up. I assume this is in the anti theft system. I ran fuel tests and had a leak into the tank. Replaced fuel pump then pulsator. Pulsator fixed the fuel leak issue. But the car still cuts out while driving or accelerating at approximately 2k. I then removed all cats to see what happened. No change. At this point it has no exhaust back and sounds terrible but full exhaust is in the future. I'd just like to get the car running right first. Fuel injectors all test fine. 16.5 ohm on all. Noid light tested all main 8. I cleaned all the relay connectors. I have noticed that my factory tach jumps kinda random when it cuts out. It will drop then go back up as I'm driving on the highway. The dealership I bought it from replaced the cap and rotor, rebuilt the transmission. Put new plugs and wires in and had a fuel pump put in. I have not double checked the cap and rotor work nor wires. I shouldn't assume but assumed they knew what they were doing. Do these issues sound familier to anyone? Is prom issues a possibility? Any other suggestions? I'm far from a mechanic but mechanically inclined and know how to use google/youtube

 

I assume you no longer have any error codes, so...

I suggest taking the ignition module out of the distributor and having it checked. Most auto parts stores can do this.

When it's reinstalled, make sure it has THERMAL (not dielectric) grease under it. It gets very hot and can fail if it's not heat sinked properly. When it fails the engine will run really badly or not at all. It will recover when it cools down.

 

Ok I'll give that a shot. And correct there are no longer any dtc codes.

 

I went ahead and removed my ignition module and had it tested 3x at a nearby oreillys. It passed all three times. Any other suggestions? I did notice the wires didn't seem all the way down when I removed the Cap to check the ignition module. I haven't reinstalled as I want to replace my oil sending unit. Hoping the wires fixes the issue.

 

Thank you cliff for your assistance. The the two loose plug wires were the culprit issue. Car is fixed it seems. Issue resolved.