So, I have a unique issue. So far I haven't found the problem after scouring all the Jeep forums and Facebook pages. I have also gone to a automotive shop. They had no idea. Unfortunately it happens at random so there isn't a guarantee it would even happen while they're driving it.


The issue: When driving around 50-55mph mostly (it has happened out of this range as well, but not by much) and giving it a little more gas either to maintain speed up a hill or accelerating mildly on the highway, it loses power and throttle response. Also the MAP drops from around 14/15 psi to between 10 and 12 psi. If I give it more gas it will pick back up, but produces a burning smell (maybe an excess fuel smell, but could be something else). If I release the pedal, wait a second or two, then go back to accelerating, then all is well, I get full throttle response and no smell). I also get the same odor when accelerating heavily from a stop or low speed. It isn't the catalytic converter, coolant, rubber, or foam burning. It also was doing this really bad one night, and ended up losing all power and stranding me on the side of the road. The CEL came on with a MAP code. It eventually started back up after 5 or 6 attempts and me banging on the throttle body for 10 minutes (I thought the throttle was getting stuck), and hasn't stranded me again since. This was several months ago. I cleaned the throttle body thoroughly and changed the MAP sensor, but the problem persisted. I have tried fuel treatments as well with no luck. It doesn't consume any fluids either. My last two tanks of fuel were 93 octane rather than 87, and it hasn't happened again. I don't want to have to continue using 93 for various reasons, and just want to understand what is happening. The CEL went off after a day or so being on so everyone I take it to acts like it is fine and it's just a Jeep thing. I accepted the Jeep thing when I bought it, but I refuse to just drive it into the ground with a ton of unaddressed mechanical issues.


Has anyone dealt with this before. I am an automotive technician myself(not by trade), but this has me stumped.

 

My V8 has been doing similar. Changed the fuel pump as the old one was 16 years old and it made is slightly better but did not eliminate the issue. Ysterday I stopped on the street and loosened my gas cap and voila all that 355HP came to life. Tank is not venting to replace the fuel being removed. Spoke with a guy who repairs Jeeps and he said it is not uncommon for the Vapor Canister to plug up or the purge system to malfunction somehow. I did not get the Jeep light for loose gas cap as I may have turned that off when the V8 went in. I may remove the vapor canister and all that crap and simply drill a vent hole in the gas cap like cars were up to the 70's. Seemed to work then. You could try the same with the gas cap loosen but you may need the system for smog tests. When I stopped and unscrewed the cap there was a rush of air into the tank yet when I look at the cap and try sucking through the vent valve it does work but has resistance. More to come.

 

Ok, so to update on Roberta. She started bogging down and eventually stalling when turning at a stop or low speeds. Same thing, wait five minutes and start her up and she drives fine. The shutter started happening more often when driving on 93 octane even. She also hesitated on two separate occasions to shift out of park. All of these various symptoms came to a head about a month ago when it stalled pulling out of a gas station on the way to work and wouldn't even turn over. I think the pcm wasn't registering that is lifted into park. At this time I got two failure to communicate with pcm codes. I verified it wasn't the ignition, fooled around with it for an hour or so, and ended up eventually taking it to the dealership after a couple local mechanics gave up on her. The dealership said it was definitely the pcm. So rather than give them $2,000, i got my own and swapped it out. I cleared all the codes, and drove until the permanent codes cleared and we looked good. Now the engine has gone back to bogging down when I turn the wheel and has stalled three more times. Two of which I had to wait five minutes or so before it would start back. The last time instead of an abrupt stall it seemed to slowly choke out. The power steering pump is not whining. Since these don't have pressure sensors or switches on the power steering systems, what regulates engine idle and power steering pressure by need?

I also replaced the crankshaft position sensor and noticed the oil pump solenoid wire was stripped so i taped it up.