LOL yes, the OP probably won't see much performance gain from dropping the entire transmission out the back of the bed. Just being silly.

 

Wow, thanks for the replys.

I'll take em in sequence.

Re-engine: the oringinal engine washed out a piston at about 160k, ran rough and when it was discovered (when i started running through 5 qts of oil in 1k miles) i found the issue and put a new engnine in it. NO, the cat, o2 sensors were not replaced.

When does it happen? anything greater than a 2-3% grade, i can't get it to go past 2,000 rpm, regardless of my starting speed on the downgrade heding into the ascent.

downshifting: starting in 5th i down shift when it drops below 1500, then it peggs to 2000-2500 and begins winding down, my foot is on the floor. Heading to Clayton Ga last year, i was in 1st 2x going up grades near the Talula Gorge.

Tires: 16" stock Coopers. Dont have the aspect ratio right now. Had Wranglers, but when they died, did not think i would be doing much hauling or keeping the truck much longer (STUPID!)

No disrespect intended if i missed a question.

I have never had a cat go bad on me, and i have no indications on the dash that i have bad sensors. I will trobleshoot the o2 Thursday. How do i diagnose a bad cat?

All, thanks again. I have reached my wits end regarding this and it is just flat annoying.

I appreciate the input. Need to get this issue skinned, cleaned and fried in two weeks.

Willie

 

Wow. And I thought I was just providing comic relief to the thread...

 

As I thought, you're lugging the hell out of it, drop another gear, let it rev, it's not a diesel.

 

There is definitely something wrong. Rip that cat off and get a high-flow with exhaust. My truck is a 99 with 5spd and 285s and 3.55 gears. I towed a 6x10 trailer completely filled with all my belongings from WA to Chicago and down to TX. Trailer is 1k dry and loaded was atleast 3x that. This is over the Rockies too. The lowest I had to go was 2nd because a semi stalled in a construction zone on an incline. I cruised in 4th (always tow 1:1 ratio folks) and went to 3rd on hills. Kept the speed from 60-05 and rpms 2-3k, never below 2k. Ill be doing the same thing here in three weeks when I leave TX for good.

 

Yeah your lugging the **** outta it. I run 1750 at about 65 mph. It rarely sees under 3k when I'm pulling, 3rd gear is your friend. Downshift when it gets to about 2300

 

Can't get lower than 1st, and can't push it past 2000 rpm once ascending a hill.

Took it to a shop and diagnosed it with the computers. Cat and o2 sensors great, all other sensors and electronic happenstance is great. Trany and rear-end are great.

Damn engine not holding compression.

Can anyone guess what i am doing this weekend?

Talk about feeling stupid.

Appreciate the input, guys. Will post the final result.

 

Compression/Leak down test

 

I would try unplugging the precat

It could.be the deaths flash ?

Our heads are prone to cracking .

When was the last tune up ,including plenum ?

 

Probably not without you telling us why it isn't holding compression What, new engine, head gaskets, heads? Don't leave us hanging man...