Hello folks. I recently purchased a 1986 C4. As far as I can tell it is completely stock. Twice now, after driving a good distance, the car lost power and died. The first time it happened was after 3 hours of driving and I didn't get all of the stats from the dash, but the coolant temp never went over 185. Then after sitting on the side of the road for about an hour, it started and ran perfectly. The second time (today) it was 95+ degrees F outside, I drove it approximately 40 minutes and it did the same thing. This time I feathered the accelerator and it actually lost all forward power as I pushed the gas down, but didn't shut off till it stopped on the side of the road. As it was doing so it backfired when I was trying to give it a little gas. Coolant was at 187, oil pressure was 58(ish) oil temp was 221 when it shut off. I was able to immediately start it (it was a bit hard to start but did do so) and get maybe 3 miles further but it had very little power then died again. And like the first time, after sitting on the side for an hour or so, it started right up and ran perfectly the rest of the way home. My mechanic replaced the ignition module after the first occasion, but obviously that was not the issue. I goolged a bit with various search parameters, but had little luck. I am a fair mechanic and am hoping to get some insight on where to go from here. Thanks in advance for any input.

 

What you describe could be the coil. They heat up (various lengths of time) and quit. Cool off run fine. Same thing with ignition module and pick up coil in distributor.

 

Yep, I tend to agree- this is in your ignition somewhere. Your engine is pretty simple ignition wise. I'm really not one to recommend "Throwing parts" ata a situation but if you are running a 35+ year system you may want to consider upgrading. The coil is an easy swap.

 

Agree with that 100% !! Only problem is finding quality parts to replace the old ones as most of them are made in covid land!!

 

Excellent not something ultra expensive and looks like I can do that here. Really appreciate your time. I love the car, but was worried it was some esoteric issue that would cost a fortune. At least I have a starting place.

 

I will see if I can find some information on upgrading the system and see what the cost and difficulty is like. Before I got married I never owned a car newer than 1972 and was able to do all my own repairs and these 350 small blocks (minus the fuel injection) are pretty familiar.

 

I agree that these days we are bound to crap parts, but if you go to Summit Racing they will have many options there. Cant personally recommend any one company, but my engine has all parts from Pertronix in it and even though they are not made here, its been flawless. My advise would be to look at the reviews and the warranty on the parts. Good luck!

 

Take a look at the fuel hose in the tank. I had an '84 that had the same symptoms as yours and that small fuel hose in the tank had deteriorated.

 

I had a fuel pump relay that would let go after getting nice and warm.