benny5.0

I have a 1989 5.0 LX with a little over 100,000 miles.

Recently it has begun shutting down after running consistently for 150-200 miles. It acts like a fuel line problem. It begins to hiccup, lose power, and eventually the engine just shuts down. I usually hear some pops in the exhaust system when I give it some throttle to try to keep it alive.

If I let it sit for twenty minutes, I can get it restarted and into a shop. If I let it sit overnight, it is good for another 150-200 miles.

But no shop has been able to find any source of the problem. The car runs fine when in the presence of a mechanic.

Fuel pump tests with good flow. No codes show up anywhere. The fuel pump relay switch and the fuel filter are new. It doesn't run hot. This problem usually happens when the temp gauge is in the middle.

I've had mechanics suggest the fuel pump relay switch (which is only 4 months old), the ignition module, and the catalytic converters.

Any ideas?

mattdel

ignition module is the #1 culprit here. this topic is posted almost daily. they fail from heat, which creates so much resistance internally that it is incapable of performing, then when cooled they worked A-OK. You'll find it bolted to the front of the distributor.

Joel5.0

The only way to ID 100% accurately what is causing the problem, is to check it with the condition present. From your explanation, the fuel pump is a good candidate followed by the TFI module. FYI.... I've had to check those types of intermittent problems after letting the engine idle for ~2 hours or more in the shop, while monitoring the fuel pressure.

benny5.0

Thanks, guys. I'll start with the ignition module. If that doesn't fix it, I'll look at other potential issues.

NotchAbove

Here is a potential answer, something to think about.

When I got my car the previous owner told me he had a problem like this and to be careful. He said it was the fuel pump, I said ok, I'll replace it.

As I am replacing it, I find out the wiring harness that plugs into the fuel pump itself did not seat fully, and must have been running like this. I am talking about the plug that goes directly into the fuel pump. I have a feel this is what caused this cars issues.
Just something to think about.