My pickup doesn't tow uphill as well as it used to. What could be the culprit?

Dear Car Talk

Dear Car Talk | Apr 01, 1995

Dear Tom and Ray:

I have a 1982 Chevrolet pick up with a 1985 454 engine. It's used to pull a 22-foot travel trailer. When this engine was first installed, it had more than enough power to run up hills with this small trailer. This past summer, it had to really struggle to make it up hills. On some of the steeper grades, I was afraid we might not even make it. We were continually passed on hills by similar trucks pulling huge, heavy 5th wheel trailers. We've been to several well-known diagnostic shops, as well as our own mechanic. All tests have shown that there is definitely much less power than a 454 should have, but no one knows how to fix it. If you guys can come up with the answer, I'll consider you geniuses of the first magnitude.

TOM: Gee, Ted. I'd be pleased if we could just get people to stop considering us dummies of the first magnitude!

RAY: Since you've been to several diagnostic shops, I'm going to assume that the compression, timing, and all the obvious "performance-related" components have been checked.

TOM: And if that's the case, you'll have to start looking into the less obvious stuff. One thing that comes to mind is a restricted exhaust system. If the catalytic converter is plugged, or if the exhaust system is partially blocked up, your power could be severely diminished. And you'd be most apt to notice it on hills, at high speeds, or when pulling a trailer i.e. when the truck is under load.

RAY: Some sort of fuel delivery problem could also cause low power. Two of the barrels of your carburetor may not be working, you may have a dirty fuel filter, or your fuel pump may be weak, just to name a few possibilities.

TOM: So that should give you a place to start, Ted. And if you hit pay dirt, let us know. I've only been called a "real genius" once in my life, and that was by my father... right after I ran his '32 Chevy out of oil. And I don't think he meant it the same way you do.

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