99 Jeep Cherokee Limited, Misfire or fuel problem?

[djhughes]

I have a 99 Jeep Cherokee Limited, 4.0 inline 6 cyl. When you first start it up it idles fine but after a few min. it starts to act like it is starving for fuel. If you take off down the road it pops back through the intake (backfires). After a few mins it takes off and runs just fine and gives no more trouble until you shut it off and it sits for awhile. Then at the next restart it does it again. It acts like a fuel problem but the way it backfires through the intake makes me think it is a firing problem. Thanks ahead of time for any and all advice.

[Saudade]

Is your check engine light on?

[djhughes]

Originally Posted by Saudade

Is your check engine light on?

No the check engine light is not on, but is has come on in the past but went back out soon after it came on.

[GTP Dad]

I'm not a Jeep man but I would pull the plugs and check them. This sounds like a misfire issue due to wet or fouled plugs. While you have the plugs out do a compression check just to make sure you don't have a bad valve. Also when did you change the fuel filter or run fuel injector cleaner last?

[djhughes]

Originally Posted by GTP Dad

I'm not a Jeep man but I would pull the plugs and check them. This sounds like a misfire issue due to wet or fouled plugs. While you have the plugs out do a compression check just to make sure you don't have a bad valve. Also when did you change the fuel filter or run fuel injector cleaner last?

I changed the plugs and wires not to long ago, the old plugs did not look to bad and were not wet. I plan to change the disturber cap and rotor button, and fuel filter and will run some injector cleaner too, and see if that takes care of it. I agree with you I think it is a misfire because of the way it pops back through the intake.

[breckin]

Originally Posted by djhughes

I have a 99 Jeep Cherokee Limited, 4.0 inline 6 cyl. When you first start it up it idles fine but after a few min. it starts to act like it is starving for fuel. If you take off down the road it pops back through the intake (backfires). After a few mins it takes off and runs just fine and gives no more trouble until you shut it off and it sits for awhile. Then at the next restart it does it again. It acts like a fuel problem but the way it backfires through the intake makes me think it is a firing problem. Thanks ahead of time for any and all advice.

my jeep is doing exactly the same thing did you have any luck resolving the problem

[breckin]

dj hughes you had a fuel problem with your jeep cherokee mines does exactly the same did you get it sorted cheers breckin

[breckin]

Originally Posted by breckin

dj hughes you had a fuel problem with your jeep cherokee mines does exactly the same did you get it sorted cheers breckin

hope you got yours fixed

[skip57]

check out the stickies at the top the 4.0 has a CP Sensor that does not set a code!!!!!!!

[breckin]

Originally Posted by skip57

check out the stickies at the top the 4.0 has a CP Sensor that does not set a code!!!!!!!

hi i live in scotland and dont know what stickies are no code is showing and wat is the cp sensor crankshaft or air temp sensor cheers breckin

[skip57]

At the top of each of the forums are help full reading IE stickies (old pages or questions that stay at the top) CSP =Crank Shaft Position sensor or Cam Shaft Position sensor. Each of these sensors work with the ECM (Engine Control Module) to set the timing of each injectors and ignition. When they are not are not working you have all kinds of problems, and the ECM goes to a mode to get you home. Bad fuel mileages is a sign that something is not working right. Each of these sensors are talked about including there locations in the above mentioned stickies (stuck at the top) May be you need a shop manual?

[Jchappy69]

Djhughes question for you, did you ever fix the problem? And if so how? I have the same problem and did all the stuff you did and it didn't fix it. Please let me know. Thanks!

[thinmints]

Originally Posted by djhughes

I have a 99 Jeep Cherokee Limited, 4.0 inline 6 cyl. When you first start it up it idles fine but after a few min. it starts to act like it is starving for fuel. If you take off down the road it pops back through the intake (backfires). After a few mins it takes off and runs just fine and gives no more trouble until you shut it off and it sits for awhile. Then at the next restart it does it again. It acts like a fuel problem but the way it backfires through the intake makes me think it is a firing problem. Thanks ahead of time for any and all advice.

Could be the IAC valve, my 96 did the same thing and once i replaced that no more problems. the part is $50 at autozone it took 5 minutes to replace