My 1997 Chevy G2500 van with a 5.7 engine and 197,000 miles has been stalling out while driving. It happens at random intervals too. All of a sudden the gauges will zero out and it will seem like everything has turned off. It only happens for like a second, then everything comes back to life and it's fine. Sometimes it will go weeks without causing this issue, then do it up to 10-15 times in a 100 mile trip. Recently it acts like it drops into neutral as well and the RPMs race until the "hiccuping" is done. I know it's not the technical term, but it's certainly what it feels like. I've cleaned the contacts on the battery and that helped for a little while a couple months back, and I cleaned the contact between the battery wire and the fuze box underneath the hood. I've re-evaluated those connections again and they're just as clean as when I polished them up, so I'm thinking it's a deeper issue than that. The ABS light flashes on and will stay on as a result of the "hiccups" until I turn the van off, then it won't reappear again. I've also checked all the fuzes and they seem fine. I've replaced the fuel pump 2-3 months ago because the pressure was too low and the starter was replaced 6 months ago. Could the issue be with the ignition switch? Are there any good ways to test this problem or to trigger it so I can pinpoint it? Could it be a computer issue? Any and all suggestions would be appreciated because I love my 350 and I figure if I treat it well, it will treat me well. Thanks.

 

Also, I forgot to mention that switching from high to low beams and vice versa causes the "hiccup". Also the turn signal and sometimes switching the radio can trigger it as well.

 

Welcome to the forum. A widespread electrical problem like that is usually the ignition switch. Try jiggling the key in RUN, engine off, lights on, and then look for brown-outs (maybe more obvious at night).

 

I tried jiggling the key while it was running and it didn't do anything, but today I'll try your suggestion of jiggling the key with the engine off and lights on. If it is the ignition switch do I have to replace the whole assembly, or could it just be the ignition relay acting flakey? Thanks.

 

The ignition switch (what's behind the lock cylinder) in those years carried a lot of current and thus the electrical contacts will degrade (wear out, oxidize) over time. However, the proper way to diagnose your problem is to check the voltage at the battery, IGN-A and IGN-B fuses under the hood, and then various fuses downstream of the ignition switch. Anywhere you see a significant drop in voltage, there's a poor electrical contact upstream.

 

I checked the fuses and they're perfectly fine, I cleaned up the contacts on them and put them back in. The problems persisted. The other day my dad was spraying WD-40 on the door hinges and the locks to keep things loose since we live in the great Northeast and the ignition key had some WD-40 residue left on it when put back in the ignition. I noticed that the van hasn't acted flakey at all since then, even though it's only been a few days. Could it be possible that there was/is some moisture in the ignition or a little bit left in it and the WD-40 on the key disbursed it away?

 

I'm more into tracing circuits and taking measurements and thus the "WD-40 in the ignition lock cylinder" hypothesis is a little too much to swallow. Maybe there's something else you did that fixed whatever it was, if it's fixed at all.

 

I think I'll squirt a bit of electronic cleaner in my ignition switch. My Tracker hiccups at irregular intervals when warm, runs fine when first started. Engine light stays off.
Also, the headlights flicker occasionally.