My 99 gc 4.0 has no power. Feels like im pulling a trailer. 50 psi at fuel rail running. No check eng light. Auto trans shifts fine. Just feels like i have to give it way too much pedal to get it to move or shift manually to keep the rpms up for power. Please help

 

Tune up, air filter, O2 sensor, plugged cat converter/exhaust,

 

No cel. Did some digging on the internet and found the MAP sensor can cause lack of power without throwing a code. I fell into a free 03 gc laredo with a trailing arm rusted off the frame free towed tomy house. Long story short swapped MAP and boom, like a new engine. Im so frickin happy. My 99 laredo is from alaska with zero rust 200k 4.0 runs like a champ. 1000 bucks. The girl drove it from Fairbanks Alaska and the rear axle seal failed in Montana. She went for it and wrecked the rea end thinking it was a wheel bearing making noise. Bought a used 3.73 put that in with new seals and bearings, gtg 😂. Love this jeep. My 1st one

 

also check your brake calipers. mine was doing that off and on and i thought it was my ac problem (ac bearings going bad) and if i turned on the ac i'd have no power, burning smell etc. and i think come to find out most of those issues was not the bearings but calipers starting to fail, had my drivers side one lock up last friday, as first well not that i tried right away ti was next to impossible to move, today it was not so hard but did get harder a couple of times.

just a thought and i am in no way a qualified mechanic just something thats just happened to me.

 

And then there is the infamous notches that the ears on the pads wear into where the pads slide on the spindle or bracket in the back. can weld them up with an arc welder and grind them smooth. That will hang the pads up.

 

Dude! The 99 has replaceable caliper brackets on the front. No need for welding the notches. Buy fully loaded calipers and you get them free.

 

Oh WORD? Will they fit a 97 zj? you mean the little tin clips that go over ?

 

Nope. The WJ's have dual piston calipers and the brackets must be removed to get the rotors off. The Teves and Akabono calipers use different brackets also.

Yardie, get yourself a can of Mr Gasket Cat-a-Clean and put it in as instructed on the chance it will clean out the converters.
it helped my 2000 very much. It had been burning oil for awhile. It's a bit pricey, but it works! $27.50 on Amazon.