so ive had this problem for a while and its been taking me forever to try and figure out the best way to describe to you guys but here is goes, ill be driving down the road and ill get to anywhere between 2000rpm and 2750rpm and my tach needle will start droping and jumping back up really rapid, and the jeep will feel like its cutting out, and it sounds like its backfiring thru the intake, ive replaced the IAC and TPS and CPS, could it be something as simple as a really dirty air filter? it also kinda feels like im hitting a rev limiter but it happens in any gear that im in at the time, so that kinda makes me think of the torque converter and ive had small issues with my torque converter not wanting to lock up. please help me im goin out of my mind.

 

isnt this your second thread for this same issue?

 

yeah my last thread was two months ago to date, i was preping for a month long field problem at the time so i didnt get a chance to test stuff and then we went to the field so i obviously couldnt test stuff. but i just did a lil test drive and unplugged the map and the idle was high when it was unplugged so the map is workin, and it ran a lil better with the air filter off so thats on the list now, so thats leading me to either injectors or a fuel pump or that pesky line that like to rot away, also the cps iac and tps are relativley new and working to the best of my knowledge at this time

 

after reading thru my haynes manual and knowing that my compression is uneven, and that this problem started some time after i noticed and checked my compression, im being led to the conclusion that its my fuel system ive got injectors to put on hopefully tomorrow, and this weekend im gonna pull the pump and check those lines, and might replace the fuel filter but im not sure about that cause its also pretty new, yes i kno it could be clogged still but money is tight and im not trying to drop too much more on jeep parts till next payday

 

maybe take the whole TB assembly apart and clean it.

 

check the Fuel pressure.

 

ive done that allready thats why im leaning towards the fuel system

 

Converter is clogged, thats the same thing my 97 4.0 did, trust me wack off the pipe in front of the converter and crank it and see how it runs, if it dnt fix just put a clamp back on it, but thats exactly what my XJ did, I mean its identical

 

bump

 

Do you get any check engine lights - sounds like a valve problem, exhaust valves sticking. Converter back pressure can cause the same problem. Usually you will get a check engine light on one of the exhaust sensors. Its a long shot you might try some marvel mystery oil in the oil and I use chemtool B12 in my fuel treatment clean TB with TB cleaner. After checking fuel pressure. run it for a wile to see if problem clears up or gets worst. Lifters could be gum up causing valves not to work. Marvel Mystery oil and chemtool B12 is what I like to use, get it a Walmart.

 

Did you measure your fuel pressure when it cuts out? Sounds like a bad FP to me.
Make a flow test too.

 

[quote=McRay;279076]Do you get any check engine lights - sounds like a valve problem, exhaust valves sticking.
x2

 

Mine was doing sort of the same. Felt like it was loading up and them would try to stall and the rpms would not stay steady. If I sat still, it would start trying to stall and only be turn 200-400 rpms. I did have a check light on and ended up disconnecting my front o2 sensor and it idled back up and ran fine. Sensor was back and was causing to much fuel to be dumped in.

 

when my converter went I never got a CEL Light, started cutting out at 4K, like the TPS was goin, then went down a real bad washboard road and came off the road and it cut out at 1K, barely made it through the mountains. I thought Fuel Pressure or TPS at first, decided to chop the exhaust in front of the Cat and, voila, ran that a scalded dog again