I found the wires are 8mm accel and have wrong exhaust I think. I had a shop bend pipes up when I put the Gibson muffler on which was 2.5 inch because thats what was on it.. So we drove it with exhaust unhooked from the cat and it ran like a race car. So tuesday we are putting on the Flow Master cat back with 3in pipe. Also the new muffler is about 10 inches larger than the Gibson, so it should help also. Any one know the correct cat? We think this was make shift, it is 2- 2.25in. in and 2.5 od single out. This seems small for a 5.8l. So we will have to take a 2.5in. od and match it to 3in. id. I will post tesday night.

 

Sounds like something booty fabbed. I'm pretty sure that the cats on these trucks had 3 inch in 3 inch out.

 

Ok guys, still need help. Put the flowmaster 3" exhaust on and welded a 3" oultlet on the gutted cat. Truck seems a little better, very little. So I jacked it up to check gears and they are 4.10 so I think there is still a problem. Would the next step be O2 sensor and some seafoam? The truck seems to have a high idle and only 64,000 miles. But it idles and drives fine, no engine lights.

 

you are letting the engine exhale better now you have to let it breeth better k&n filter at least, yes try the seafoam, sounds like the exhaust thas some restriction in it if it runs alot better with out any exhaust, what kind of mufler? is the truck pretty loud? really the louder it is the less restrictive the muffler is

 

heres a question, was the cats gutted prior? you may have material in the muffler thus your clog.

 

The truck has a k&n intake on it already. The cat was gutted last week and I did find stuff in the old muffler. The flowmaster is clear and for single exhaust quite load.

 

What size tires are on this rig?
What year is the truck again?
How much does the truck weigh?

You may be simply asking too much from the vehicle. It's entirely possible this thing weighs 2000lbs more than the Jeep, so even if the engine is a bit more powerful, the advantage is sucked up by the extra weight.

 

The truck is a 1995 with 265/75/16 mild at's. I did rear brakes tonight and found the passenger rear had the e-brake slightly on. It did run a little better after brakes were on and e-brake was off. At 12 years old should I change the O2 sensor or will it throw a code when its bad? Is there any emission stuff that causes poor performance with out throwing a code?