Intermittent Power Loss in 1989 Chevy G10 Van with 305

sounds like a throttle posotion sensor. does it idle good, or does it go up and down? i saw u replaced plugs and wires, what about dist. cap and rotor button? really sounds like TPS though. hope this helps matt

Thanks for your idea. We also changed the distributor cap and rotor. It idles fine when not experiencing the problem. Then when it happens it dies at idle and needs to be started again. The idle doesn't go up and down.

Do you still think we should try TPS or is that only a suggestion if the idle goes up and down.

We really appreciate your suggestion because everyone who has looked at it has failed to find the problem and that has never been mentioned. Thanks.

No, the van often works fine for many days or many hours. Sometimes we go weeks with no symptoms. We haven't been lucky enough to have it happen in a shop.

And it isn't getting more frequent. This has been going on for over a year and we still haven't hit a consistent period when we can get it into a shop.

Thanks

I don't know what that engine has, so this may not apply. But, we had a Buick of (IIRC) 1980's-vintage that acted like that. The problem was a bad intake airflow sensor.

Other vague memories: EGR? vacuum leak?

I just checked the records and both the throttle position sensor and the air control valve *were* replaced. Neither of these fixed the problem.

The fuel pump has not been replaced but the pressure checked fine in the Chevy dealership.

The coil has not been replaced.

What does it do when it fails? Any backfire? Does it just abruptly lose all power, or gradually slow down, or ...? When you give it more gas, do you get any response? Do you hear anything?

And, for how relatively little it costs, I'd probably replace the coil.

Not getting pinging associated with it when it happens, are you?

The HEI distributors' centrifugal spark advance would sometimes hang fully advanced intermittantly (rusty), usually after a hard acceleration, then when you stepped down on it again, you'd get flat reaction and hard pinging...

Not sure if '89 still had the mechanical advance either...

Is that carb'd or TBI?

When if fails it just cuts out with no backfire, no sputter, no gradualness. If you then give it gas there can sometimes be no power at all or, other times, much reduced power, almost enough to maintain speed but no possibility of accelerating. There is no unusual sound.

I have been carrying both the coil and the computer which I will now replace but am trying to collect a list of all possible options to do them all at once. This issue has been such an aggravation in its tendency to reappear I really want to try to put it down once and for all.

Thanks for the guidance.

There is no pining or other remarkable sound but thanks for the perspective.

It is an early fuel injection, not carb.

Thanks for thinking about this. We are beyond stuck.

Today, installing the coil and then an ignition module I looked carefully at the connectors, as various Chevy shops had claimed to do. In fact the connectors to the latter were corroded. I suspect this will resolve the problem and most components are replaced anyway.

This to me was coming across as an ignition module issue, hopefully cleaning the corrosion fixes it!