Hey guys I have a 1999 Cherokee with 106k. When I bought it I went through it completely and replaced most of the cooling system. I also replaced the head gasket that was leaking.

Well today I was driving up mt. Charleston and all of a sudden I had no power (flooring it got me just under 40mph) and it started overheating.

I turned around and drove it home and it was fine, no overheating but on a flat freeway I could only maintain about 60. Last week I could cruise control it 80mph without an issue.

I checked the codes and nothing is showing. From what search I've done I'm thinking MAYBE a broken flexplate? There was a small bit of rattling when I started it and after letting off the gas at full throttle. But both of those went away at this point.

Anyone local that knows more about these than me willing to take a look at it, I'm going crazy and its my daily driver. I hate to take it to a mechanic that will fix 10 things before finding the right one, money is tight. Any help or advice would be greatly appreciated

 

ok, just removed the flex plate cover and peeked inside, nothing looks cracked or broken. Any ideas, I'm lost

 

When was the last tuneup? Start with the small things first. Have you checked the fuel pressure? I'm assuming you have the i6?

 

Tune up was a few months ago. New everything. No on the fuel pressure, I don't have a gauge to be honest.

 

A friend had the same thing happen coming over the hump to Pahrump and it turned out to be a clogged up cat.

 

From a dead stop, floor it. Pedal to the metal. A clogged cat will cause the vehicle to sputter or hesitate as it picks up speed. Usually resulting in the vehicle not exceeding a certain MPH (most common at or around 40mph). This will also cause it to run hotter than normal.

If/when you change the cat, replace the O2 sensors as well.

I got quoted $100 at Best Muffler Shop for the cat replacement and $280 for a complete exhaust with muffler and cat installed... just to give you a rough ballpark figure.

 

Ok, Ill try that today, thanks. Ill get back as soon as I do that

 

I don't think its the cat. I can accelerate smoothly and quickly upto 50 with no hesitation or sputtering that I can notice. Tried it a few times with no symptoms. Any other ideas?

Could it be the flexplate if its showing no visible cracks?! Maybe the fuel pump or transmission?!

 

Does it stutter at all? Like feel like its missing?

 

Mine would run hot on the freeway in the summer and cool on surface streets. Driving on the freeway was a chore because it seemed to hit a wall at 65mph. I Checked my cat and fuel pressure. The cat was good. The fuel pressure was good at low speeds. I was unable to check fuel pressure at high speed.

I put in a new fuel pump a few months ago and that sucker has way more power now and starts right up on the first crank.

Prior to the fuel pump I'd have to hit the starter 2-4 times before it would start and since the pump wasn't up to snuff the motor would lean out and heat up under load.

Could be that.

 

No, not that I can tell. It starts right up and is smooth. I've just lost top end power and going up an incline it cant get over 40mph and overheats

 

Maybe, this thing should be running cool as possible. I cut two massive vents in the hood, installed a new radiator, high flow water pump, high flow thermostat housing, and a high flow 180 degree thermostat. When it was overheating I was shocked

 

Well you've got an issue, try the fuel pump as it sounds like it could be a issue..
99 right? I think these had the remote filters in the tank itself, as in not change able. So chances are it could be clogged?

Any air pockets in the cooling system? Also check to see if your headers cracked..may as well knock out some of the big issues while your fix it.

 

I'm trying to find a fuel gauge to test the fuel pressure today, if anyone in vegas has one I'd love to swing by and test the pressure.

How would you check for air pockets in the cooling system? I still don't see that effecting power, because the loss of power came before the overheating but its easy to fix if it is.

I really need to make sure what part is broken, I just dont have the money to be replacing parts that aren't broken.

 

I installed a96+ thermostat housing, they have the temp sensor in the housing. I put a small/short bolt there instead because on my 88 the temp sensors on the back of the head.
Anyway I just unscrew that bolt ever so slightly while the jeeps running and any air will seep by after a few moments and then tighten up and your good to go.