Man, I just don’t understand something. All you guys are supposed to be the be-all end-all experts on this stuff. I don’t understand why nobody can give me a specific answer and action plan on a truck they’ve never seen, that’s 1000 miles away from you, that has 320,000 miles on it, that has also been highly modified. And I thought you guys were experts.

Seriously, though, I greatly appreciate all the comments and advice. I was considering pulling the top off the engine to change the injectors, and some other things, but I know just enough to know that that doesn’t feel right to me. I’m coming to the conclusion that it is the catalytic converter, and that’s a very easy thing to check and start with.
My rationale: when I noticed the drop in power, and then a significant drop in power, I noticed a ton of soot in the driver side exhaust stack, and I changed the plugs. One was loose in the threads, but very loose w/blow by from not being seated properly, and it was black with soot. That large amount of soot had me thinking the cat might be partially plugged.
Then I added the varnish remover/injector cleaner, and the situation immediately got much worse. Part of my thinking was I pushed crud into the injectors, but my current thinking is any crud that came loose further impacted the cat.
Side thought: A few of you have seen the truck, and when my exhaust guy put in the dual exhaust and stacks, he kind of did a half assed job of looping the driver side underneath the frame right behind the cat, which gives me another reason to mess with that area.
So here’s the action plan: I didn’t know you could buy a cat for like $80. The cats I’ve bought before were in the $500 and up range. I ordered a couple band clamps, and a short piece of 2 inch pipe to evaluate the problem. I’m going to cut the cat out and put the straight pipe in and see if that solves the problem. If it does solve the problem, I’ll buy the replacement cat and go to a better shop to put it in and do a better job running the pipe under the frame. What I went to dual exhaust and the stacks, the gas tank was in the way on the driver side, hence routing the pipe under the frame. I’m not worried about clearance, this truck will never see any significant off the pavement use.
If that doesn’t work, I’m going buy all the parts I can think of, and let my shade tree take the upper intake off, and maybe check some other things like the rockers and push rods.
The parts are supposed to be here in about a week.



