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cautiocones 09-13-2012 03:32 AM

94 yj bogging down/sputtering/high fuel press.??
So when my 4 banger gets warm and I'm driving around town I'm having an issue with my idle, it will idle about 800 them drop to about 3-400 then back to 800 and keep fluctuating like its going to stall but it won't. It will also act like its going to bog down when I'm driving and hit the gas it feels like it hits an RPM rev limiter, and I get a loud popping/backfire kinda sound from the engine compartment, any ideas?? Iv replaced everything and I'm running out of ideas! I haven't done a compression check though, could it be a clogged exhaust system? I also have a fuel pressure of 55 psi at the rail with the vacuum tube on or off

This is what Iv replaced - TPS,IAC,Fuel filter, fuel regulator,cleaned injectors, oil change "came out normal" , air filter and cleaned my throttle body and new vacuum hose on fuel regulator and case vent.

I know my muffler is bad due to the chunks rattling around and I think my cat might be bad too?

Pullsout 09-13-2012 06:48 AM

After all the other stuff you've replaced I would think that the exhaust is going to be your only other option. If exhaust can't get out you're gonna have a bad time.

Tyewilly 09-13-2012 09:33 AM

Check the vacuum line to the map sensor, the factory plastic vacuum lines have a tendency to get holes rubbed in them from years of vibration.

jfbilbro 09-13-2012 10:59 AM

It could also be the crank position sensor, but a clogged cat will do that too....

cautiocones 09-17-2012 06:46 PM

Well I feel stupid, wound up being a loose distributer shaft, had about an 1/8th of an inch of play when shaking it around -_-

Pullsout 09-23-2012 04:55 PM

it's always the littlest things that get you

matrix311 05-17-2013 01:10 AM


Originally Posted by cautiocones (Post 2802148)
Well I feel stupid, wound up being a loose distributer shaft, had about an 1/8th of an inch of play when shaking it around -_-

I have identical symptoms with my 2.5 right now. I really hope this is my problem and plan on checking it out tomorrow. I will post results.

voyager_1700 05-17-2013 06:59 AM

Hey.. I just ran into a similar issue.. My 93 6cyl idle would surge.. then settle back down.
I got a code 51 (O2 sensor reporting lean condition). She was running rough on the way home.. I was poking around and noticed the back 3 fuel injectors were loose.. Then the magic Check Engine light came on and now I was getting Code 27 (Fuel Injector Control) as well as poor fuel economy about 10mpg
It turned out The fuel return line was crimped restricting flow back to the tank causing high fuel pressure (My mech told me 90 pounds) Causing a rich condition fouling out my plugs and o2 sensor was toast. Just got it back last night no surge and running great..

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