Allright heres what happens.....

Start the engine....starts just fine with no problems.....try pressing the gas and I get flat spots in power while on the gas, but it idles just fine....this problem would usually clear up just fine, but lately things have changed.............

now, the car starts fine and has its little flat spots like usuall, but then, a few miles down the road, it will try to stall on me while I have the clutch in to shift. When the clutch is released, engine rpm will stick at anywhere from 1500-2000 rpm. until it tries to stall again and the same thing happens.:barf:

Anybody have any similar problems with their early 4.0L. Any ideas.

I was thinking either the Cold Air Start Sensor or the Throttle Position Sensor.

Dunno if it helps but when my TPS went bad... the idle was NOT fine. It was idling real rough.

It also wouldn't accelerate... pedal to the floor but the motor would sputter & choke, etc etc.

Originally posted by big4294x4
now, the car starts fine and has its little flat spots like usuall,

Your Jeep just hates you calling it a car.:flipoff2: Stop that behavior and everything will be fine.:rasta:

TPS, fuel filter, vapor lock (does it do it cold or just hot), carb rebuild? Lots of stuff it could be.

Sounds like a plugged Catalytic converter.

Always start with the easy, cheap and regular maintenance stuff. Change the fuel filter!

87 where FI so no carb problems.

Originally posted by Weasel
87 where FI so no carb problems.

Clogged injector?

Originally posted by Keith Strong


Clogged injector?

In 87 it would be more of a leaky injector instead of a clogged one.

I don't think it would be clogged injectors or fuel filters or any of that stuff becuase it seems his problems are when he touches the clutch. No of those items above have any connection with the clutch so if they where malfunction it would be all the time. But I can't tell ya what's wrong either.:(

well, pushing in the clutch changes the revs doesnt it? thus changin fuel consumption in some way :rolleyes: Does it make a difference at idle pushing the clutch in or not?

Can somebody verify this:
I think the computer system in the 87's had some problems causing stuff like this.
I had an '88 & I remember being told that betw. 87 & 88 Jeep fixed some sensors that went south....

Try some of your fuel/emissions related sensors, but I'm almost certain the TPS would have different problems.

I'm a newbie bitch, sure, but I'm just throwing out suggestions.

I did notice a leaky injector today. How much for a new injector?

I will replace my fuel filter tomorrow just to eliminate it. And pul the plugs to see if I can locate a clogged or bad injector.

It idles fine, but when I do press the gas to accelerate, it sputters, coughes, and flat spots. I was just using the clutch as an example of how quickly the engine wants to die when the RPMs drop. When it runs at a set RPM and I do not let off of the gas, it sounds like its running fine.

Oddly enough, it drove fine just now when I drove it to practice and back (about 10 minutes)

I am also going to try cleaning the sensors and my throttle body tomorrow.

Thanks for the help with my car problem, oh sorry its a Jeep:D

check the cam position sensor (sync sensor, whatever) it's in the distributor. my buddy's 90 4.0L did the exact same thing. it turned out to be that little bastard.

unhook the sensor, drive it, and see if it makes a difference. if it does, replace the sensor. (replace the whole distributor, the price difference is about $3, and i think the distributor as a whole was actually cheaper)

if i remember anything else from this, i'll let ya know. too much:smokin:

oh, and replace that injector ASAP, you can use ford motorsport mustang 19#/hr injectors, and a set of 8 can be had for around $200 leaky injectors are a BIGASS fire hazard. ask DILLINGER about that one.

http://www.bigoffroad.com/images/bigpages/bigpics/submitted/bigrig/dillinger/dillinger4.jpg

that no longer exosts because of leaky injectors (maybe it was o-rings, but that's not the point)

I have an 88 cherokee similar probelem just started this summer.
I do have a leacky injector, need to fix that, and I think it could be the TPS.

Mine acts up when the engine has sat for 7hrs or more but most of the time it drives fine, Its always hot in AZ so its not temperature related.
When it acts up a full mile of driving the engine will clear it right up? if it goes into the sputter Ill hit the clutch and give it gass It cuts out and back in sometimes you can hear a quite pressure release puff from inside the engine compartment just before the engine kicks back in.

Im guessing electrical sensors becuse its not temperature dependent and most of the time works fine, or loss of fule pressure. I had a similar problem with our Dodge neon it even sounded the same, the TPS fixed it.

I must have good fuel pressure at start up becuase it starts ok, well ya know, starts like a jeep.

Ill first replace those slightly wet injectors. (safety)
Ive replaced the old spark wires
have a new dis cap to install
should replace my fuel filter and check the fuel pressure for consistancy. could be a half working fuel pump.
Then Id replace the TPS sensor, check the emmisions sensor on the exhaust.

Im thinking TPS...

Well, I pulled my plugs.....none were fouled.

Next, I pulled the TPS sensor and just exersized it to make sure that it moved properly, then I took the Cold Start Sensor off and examined it.

About half of the temp sensor (the little tip that extends into the throttle body) was covered in carbon deposits. A little sandpaper and 3 minutes later it looked almost new again (at least on the outside). The jeep started fine with no flat spots or coughing and the RPM never shot up.

I thought that I had the whole thing fixed, because it ran flawlessly for about three drives ( each about 5 minutes long) and one quick wheeling venture.

However, the Jeep finally just died pulling into my neighborhood. When I depressed the clutch to downshift from 3rd to 2nd allowing revs to drop, the engine simply stopped running. Any ideas?

Originally posted by 1337j33px0r
check the cam position sensor (sync sensor, whatever) it's in the distributor. my buddy's 90 4.0L did the exact same thing. it turned out to be that little bastard.

unhook the sensor, drive it, and see if it makes a difference. if it does, replace the sensor. (replace the whole distributor, the price difference is about $3, and i think the distributor as a whole was actually cheaper)

if i remember anything else from this, i'll let ya know. too much:smokin:

oh, and replace that injector ASAP, you can use ford motorsport mustang 19#/hr injectors, and a set of 8 can be had for around $200 leaky injectors are a BIGASS fire hazard. ask DILLINGER about that one.

that no longer exosts because of leaky injectors (maybe it was o-rings, but that's not the point)
Yea Like I said I also have leacky injectors, do you reccomend replaceing them all or just the two. Just never worked on injectos before.

so the mustangs? is it a better performing injector? Any Ideas on the Jeep injector's cost? I might tackle this on Friday, so if anyone can respond today that would be great.

thanks guys

Before you spend some cash to replace your TPS (most likely problem), pull all the sensor plugs and shoot some electrical contact fluid into the plugs and work them a bit. Especially the TPS circuit and the speed sensor (CPS)on the bell housing. If you have an intemittent open there the computer has no idea where top dead center is. I wonder how many thousands of sensors were replaced by the Jeep dealers when a quick working of the plug would have solved it. I've had 3 Jeep, I-6's with both the French Renix '87-90, and Mopar F.I. systems ('91- present).
Regards, as always, jefe