[PonchoV8]

It's not the EGR. I swapped it with my 98 Tahoe and there was no change.

[dreamingmuscle]

Tin Injun Tom's post reminded me of a problem I had with a 76 Datsun pickup.

It would spit and sputter most any time it got below 3/4 of a tank. Never did figure it out. Thought it was water in the tank. Dumped all kind of dry gas, rubbing alcohol into it trying to get rid of it. Finally found that it had a drain plug and drained the tank. It had a little water in it but not enough to cause the problem.

My brother sold it to a friend of ours after I joined the Army. He dropped the fuel tank and found the fuel return line had dry rotted. He replaced the return line and it ran fine.

Glen

[PonchoV8]

Well, it looks like a plugged exhaust is the culprit. I pulled two of the O2 sensors and drove it for about 15 mintues. It looks like that's the deal. I can bang on the cat and hear stuff rattling inside of it.

I bought a fuel pressure tester yesterday and it was rock solid on 55 psi. Revved it up and listened to the exhaust and I could hear the constricted exhaust. Looks like a new cat and muffler are needed. Odd that it happened when it did, but at least we weren't out of town when it happened.

[md1twal3]

Originally Posted by PonchoV8

Well, it looks like a plugged exhaust is the culprit. I pulled two of the O2 sensors and drove it for about 15 mintues. It looks like that's the deal. I can bang on the cat and hear stuff rattling inside of it.

I bought a fuel pressure tester yesterday and it was rock solid on 55 psi. Revved it up and listened to the exhaust and I could hear the constricted exhaust. Looks like a new cat and muffler are needed. Odd that it happened when it did, but at least we weren't out of town when it happened.

Not necessarily odd, Doug. Some low end gas can burn slower, creating hotter cylinder area. That equals hotter exhaust into an already tired cat can burn it down.

Congrats on the cheap fix (compared to replacing the truck) and keeping it on the road!

[dreamingmuscle]

Well did it work?

[PonchoV8]

Yassir it did. One hundred and twenty dollars with tax for a new cat, and it's as good as before the event. Thankfully they popped the O2 sensor back in too. Thanks very much. I wish that I'd pulled the sensors earlier. I was afraid they'd be rusted in place. They said my innards were still intact, but were clumped up. Good advice on the diagnosis!

And I got a letter from the Dept of Ag Weights and Measurements people. They went to test the pump and since the price was different, they didn't test the fuel. Lovely, government in action, gotta love it. Drove out there and went back for nothing.

Thanks all!