Intermittent Missing, Skipping, & Stalling

astro
chevrolet

#1

This one is long running and frustrating. 94 Chevy Astro van. A long time ago, my engine would sometimes just suddenly shut off as I’m driving (usually at highway speeds). This was VERY intermittent - perhaps once every few weeks or so - but in time it became more frequent. Most of the time it would start back up immediately, but sometimes it would take a few minutes or even a couple of hours. The engine/starter turned over just fine, but it wouldn’t catch. The first diagnosis was bad/contaminated fuel so I used “Heet” and other products and it SEEMED to fix the problem. But then it returned, and started to get worse. After many different mechanics looked at it and weighed in, I ended up replacing the fuel pump and filter, and checked things like vapor lock, the EGR valve, cleaned the injectors, etc. Each time it seemed like the problem was fixed but it eventually returned. Then I started having a similiar (related?) problem - the engine would miss and buck every now and then as I was driving, and occasionally still would shut off. This got worse and worse and the vehicle became undriveable. Again, a few mechanics had a go at it and this time I ended up replacing the plugs and wires, the wiring harness to the injectors, the entire injector assembly (expensive!), and the distributor/cap/rotor. The one thing that SEEMED to actually work was the new injector assembly. That was a year ago, but now the problem has returned.



Every mechanic I’ve talked to is stumped. And I’ve run out of ideas. Your help is appreciated, thanks.


#2

Keeping it really cheap, just for the hell of it, disconnect the battery, access the computer and make sure none of the plugs are loose. Actually,disconnect one by one and plug them back in. Please,touch metal while you are doing this.

You may have a bad or dirty connection.


#3

I wonder if perhaps your fuel pump is intermittently dying, or having its power supply interrupted at the connection near the fuel tank. The wiring harness might be dirty or rusty and need to be cleaned up. Access to it is real tight, but it’s worth looking at.