XJ.89.Limited

So for the past 2 days my little renny has been very odd. Here are my two points:

--I start it, it runs, sputters, then dies. It doesn't do this every time, but it did it about once a day since monday or tuesday (can't remember exactly, school has fried my brain). Anywho, it also idles fairly low at times and I can't figure out why. I sprayed TB cleaner around all the vaccum lines and intake ports, and nothing happened. It just sizzled and evaorated. Idle stayed the same. It goes through a cycle of normal idle, then low idle, then normal again for about 10 seconds per cycle. When in drive and stopped, it idles low. All this is more drastic when the engine is cold.

--On medium acceleration (like half-pushed pedal) I can hear a scraping/squeaking/tapping noise coming from somewhere underneath/the back. It's kinda like how an exhaust leak sounds on an old v8 pickup, but more mechanical. It also speeds up with engine rpms. At 2000rpm it kinda sounds like a turbo, but more of a squeaky air sound at that point. I can't hear it when I rev it in neutral, but the engine pops when idling down again, like on a stickshift when downshifting. I also noticed that when the tourque converter locks up around 45mph and it goes to about 1500rpm, it sounds like a diesel lope if you are familiar with that. The amount of gas I give it makes it louder and more noticeable. It's not a constant deep tone like usual, it sounds like it comes in waves. Quiet, loud, quiet, loud. About a cycle a second. I have a cherry bomb extreme on, so I can hear the deep tone better than with the stock exhaust. This all just started happening yesterday.

--I'm stumped on what these could be Seems like my mpg has gone down and I have a little loss of power also. Any help would be greatly appreciated!

DeadCellM60

Without being very well versed in the wonders of the Renix I'll still try to offer ideas.

The low and jumping idle I'd contribute to a TPS.

The strange starting/running rough/failing to stay running could be anywhere from a fuel pump to a CKS. How is the quality of spark and what is fuel pressure like? Are all the vacuum lines tight? This could also factor into the low mileage.

The noise from the rear could be a few things. The first I'd suspect though is a U-Joint. Crawl underneath and give everything a good shakedown and feel for any looseness.

XJ.89.Limited

Guarantee it's that damn TPS acting up again. It was acting up and made it idle too high before. I just recently changed the crank sensor (PITA!) So that shouldn't be the problem. The spark is pretty decent since my dad and I checked it when we did the sensor. Not sure about the fuel pressure, bit it's probably not too high anymore. All the vacuum lines are good. One has a hole in it but I never had a problem with it and I'm not too sure exactly what it does. It runs behind the engine to a canister thingy by the distributor. I checked the U-joints (front and rear) not too long ago and they were fine, but I can always do that again since it takes only a minute. I have a feeling it has to do with either the rear brakes or the diff. Hopefully not the diff.

cruiser54

Check and see how much voltage you have at the rear terminal of the ballast resistor with the Jeep running. Should be around 10.2 volts.

XJ.89.Limited

Rear what of the who now? haha. Explain a little more on that please. I'm not too good with electrical words. Give me a location and description and I can probably find it.

cruiser54

The fuel pump ballast resistor is a white ceramic dealy about 3" long on the driver's side inner fender near the air cleaner. Should have 12 volts or so at the front terminal and 10 volts at the rear terminal with the engine running.

XJ.89.Limited

Much better, haha. I think I know what you're talkin about now. I'll have to check tomorrow when I get a chance. I have classes from 9 til about 2 so I'm gone most of the day.