Chevy Van cuts off in hot weather
I have a 1995 G20 van. I got it two years ago with 60K and it is a wonderful van except for when the outside temp gets to be over about 87 degrees. And it just shutters a bit and cuts off. It starts up again, but if I’m not on the gas, it will shutter and cut off again.
it’s my work van and it’s nerve wracking to have to pop it in neutral and crank it while driving down the road.
I’ve had three mechanics look at it and test the fuel pump, but they say it’s ok. I’ve posted on Chevy forums and no one have a clue what the issue could be, no codes, no other issues. As summer comes to an end, I am really trying to fix it now because before long it will be cool again and I won’t be able to reproduce the problem if I need to. It was only 85 degrees today and it didn’t cut off once. But two more degrees and I can expect the most annoying ride when I let off the gas.
If you wanna check for vacuum leaks - you'd need a smoke machine (maybe at your mechanic's) or make a DIY one.
For DIY you'll need an air pump, a jar with winding cap, a couple of tire valves (if my translation is correct), two flexible tubes that fit the valves and a pack of cigarettes. There's a whole bunch of tutorials on Youtube for different "styles".
Then you plug the main intake right at the engine housing (a plastic bag with rubber band should do the trick; if there's a MAF sensor - better to take that off too) and connect the smoke machine where the PCV tube connects to the intake (disconnect the PCV tube, obviously). Start the smoking machine and look for smoke escaping the intake with a flashlight.
If I'm correct, your van has pretty much the same engine as my S10 Blazer (a Small Block V6 or V8).
I ran into similar issues recently and the root of the problem was the ICM. Those things live inside the distributor and are affected by heat.