Greetings from Indiana, and my XJ is acting ODD. HELP?

SurfXJSnow

NAXJA Forum User
So, were on our way back and something is seriously off with my jeep. This morning when we took off everything seemed fine. Then, coming off an exit in West VA earlier i noticed as i was slowing down, my engine seemed to be "putting"... Meaning my muffler sounded more "put,put,put" then usual. So i hit the gas to accelerate and noticed my jeep accelerate kinda jerky, like it wanted to stall. I popped the hood at the rest stop and noticed the engine seems like its shaking around a bit more than usual. Jeep is idiling a little below the "1" on the guage, which i guess is 1000 rpm? The thing thats weird is that when i hit the gas, it sounds just fine and stops shaking, and when im doing anywhere between 10 to 80 mph i dont notice a change... its only when going around 5 mph during acceleration and when idiling.

Spark plug? Spark plug wire? bad gas? We made it to indiana without it stalling out, but we're going through Kansas tomorrow so i want to make sure its nothing serious before i break down in "Nowheresville". Thanks in advance.
 
I'd say TPS before CPS, but that's me.

If it runs OK on the highway, put some injector cleaner in the tank next time you fuel up and drive like you stole it.
 
so you think it could be dirty fuel injectors?
...bad gas, fouled spark plugs, the list can go on. Brand name injector cleaners claim to clean the intakes and combustion chambers as well.

I've been through Throttle Postion Sensors on a few cars, always starts failing at the speed you drive most. Not to mention that it has moving parts to wear out and change electrical values.
 
I'd say TPS before CPS, but that's me.

If it runs OK on the highway, put some injector cleaner in the tank next time you fuel up and drive like you stole it.

X2 on the TPS. Sounds just like the issue I was having with the '96 when I first began working on it.

To replace it, you'd be best to remove the air intake tube, throttle/cruise linkages and unplug the connectors for the TPS, and IAC. Use a 10mm socket and remove the 4 bolts around the throttle body and remove the entire throttle body - makes it MUCH easier to get at the torx screws holding the TPS on. Then remove and replace the TPS and reverse the process to reassemble.
 
Last edited:
I know it is not his CPS (Crank Position Sensor) cause I am sure his bell housing is not loose like mine was. Low RPM miss has been ignition most of the time for me. Never had a problem with my TPS of coarse I have a Renix 4.0 and I do not know how often those go south on a Renix. I would think you could make it no problem all the way home.
 
I have a 2000 xj with 130k miles, and it has been doing the same thing. First I changed the spark plugs (i would have done the wires too, but i have the distributorless ignition system), then i ran some bg44k through it, but it didnt fix it. Then when we were down at surran wrap it wouldnt start back up on the trail. I replaced my crank positioning sensor, and now it is a lot better, but still does it once in a while. If it continues, i will do the tps.

Start with replacing plugs and wires first because they are cheap and it could probably use it anyway, and then if it still does it, take it from there.
 
Thanks guys. Im going to check the TPS first, then the CPS, then the plugs, then the wires.

Posted a thread up on the main board and a guy in Missouri right off of I-70 responded and said i could stop off at his house and he could hook it up to his computer to read the code for the Check Engine Light. Then maybe be able to diagnose the problem before i drive through good ole' Kansas. PM'd him with my number so maybe he will call. I wouldnt be so concerned with this if i wasnt driving through Kansas today. For those of you that have driven straight across, you can probably understand my worries. H

Have 1000 miles left to COS, may try to push it and get in late tonight, but thats doubtful. Probably be back tomorrow. Ill keep you all posted.

THANKS AGAIN!.. NAXJA ROCKS. :yelclap::yelclap:
 
Thanks guys. Im going to check the TPS first, then the CPS, then the plugs, then the wires.

Posted a thread up on the main board and a guy in Missouri right off of I-70 responded and said i could stop off at his house and he could hook it up to his computer to read the code for the Check Engine Light. Then maybe be able to diagnose the problem before i drive through good ole' Kansas. PM'd him with my number so maybe he will call. I wouldnt be so concerned with this if i wasnt driving through Kansas today. For those of you that have driven straight across, you can probably understand my worries. H

Have 1000 miles left to COS, may try to push it and get in late tonight, but thats doubtful. Probably be back tomorrow. Ill keep you all posted.

THANKS AGAIN!.. NAXJA ROCKS. :yelclap::yelclap:

Yeah, that straight shot of I-70 is hypnotic!! Be careful and stop several times to break things up!
 
UPDATE:

Stopped at LEFTLANETRUCKING's house in mid missouri earlier on our way back. First off, what a great guy... invited us in with open arms and even had a diagnostic computer thing he plugged in. Once plugged in, it gave us an instant "Cylinder 1 misfire" code. We pulled the plug and wire to cylinder one and noticed they were both in need of replacement. Checked the distributor and the rotor and both looked like they could use replacement as well. His wife drove up to advance and picked us up a new cap, rotor, wires, and plugs. Replaced them all and still had the problem. Hooked up the computer again and gave the same code "cylinder 1 misfire". We then pulled the cylinder 1 fuel injector and installed a spare he had laying around and things seemed a bit better. We then found a small leak where the fuel injector for cylinder 1 connects to the body of the motor. Fixed that, then we got "no problems found" on the computer. Drove it around the block and things seemed to be fixed until i was pulling it back in the garage and it started the putting again. Just a really choppy idle is all it is. Jeep runs fine at high speeds, just a little choppy still at 5mph. No biggie. Ran diagnostic one more time before we left and got same code "cylinder 1 misfire". So TPS now? CPS? All new plugs, wires, cap, rotor and replaced cylinder 1 fuel injector. All other injectors look clean. All plugs sparking. All electrical outlets on fuel injectors are giving a good pulse (hooked up electrical light testor). Anyways, we made it to topeka, should be home tomorrow before the big storm.

and thats the update from a day of hell on the road. =)
 
Uh oh........ I'm a little concerned about it being specific to cylinder #1 after all those parts have been replaced/inspected........ In my experience, I've seen 3 '97+ engines that have had the head gasket go bad between cylinders #1 and #2.

Sounds like you may be getting the spark quenched..... by a leaking head gasket.

Be sure to check your antifreeze level. If it's above the "add" level in your overflow tank, keep an eye on it and see if it goes down over a short time. If it's below the "add" level, fill it and again, watch to see if it goes down. If it's empty..... definitely fill it asap.

When you get home and the engine has cooled, pull that #1 spark plug and see if it's wet at all (not likely if it's a small leak) or if it's fouled up. Compare it to the #3 plug.
 
Last edited:
hey bud im off all day tomorrow...
hit me up if you get into colorado but cant amke it home or something...ill come help out...
hopin its not the head gasket...that would suck!
troy why do those do that?...different head?
 
troy why do those do that?...different head?

'99/'00 model years are bad because they did go to a different head during production and they can either crack, or warp allowing the head gasket to leak.

Jonathan's is a '98 and while not a prolific problem, I've seen several - I wanna strike it up to poorly maintained cooling systems. All it takes is to overheat our wonderful little 4.0's just once real good and that'll start the problems......

That white '96 I fixed, lifted and sold a while back had been overheated, then the radiator cracked so the owner dumped too much stop leak in and caused it to continue to overheat worse. The head gasket went kinda suddenly I think because when her friend removed the head to put a new headgasket on it, there was a silver-dollar sized hole in the top of the #2 piston. Generally, to get a hole in the top of a piston, you gotta drop a valve in there, or suddenly cool it with a fluid leak.......

That silver '00 I just sold had badly bent push rods and a slightly tweaked #2 cylinder piston rod. It's my guess that the head gasket burst and filled the cylinder with fluid and it "hydraulic-compressed" during a compression or exhaust stroke - keeping the valves from opening and thus, bending those parts....... :dunno:
 
well shit. head gasket huh? well i made it back. Jeep is still idling a little choppy but drove well at 70 mph all the way through kansas. It overheated once in Hays, KS but i was doing 80 at the time. Just slowed down and the temp went back down to normal. SO what now? Check plug 1 to see if its wet? what kind of wet? oil wet?
 
ALL of the old plugs we pulled out we're kinda white. Kinda like a beige color. Not on the post, but on the sparking end. I'll pull cylinder 1 plug tomorrow and see what 800 miles from missouri to colorado did to it. Lets say it was the head gasket... how much money am i looking at? Another thing i was thinking was that cylinder 1 may be siezed up? When we pulled the electrical harness off the fuel injector to cylinder 1 we felt little to no difference in the way the engine was running. When we pulled cylinder 2 electrical harness to the fuel injector the engine started getting really choppy. All cylinders are getting spark and fuel though. Tested all plugs and electrical to all fuel injectors and found no problems.

Here is what the guy that looked at it from missouri has posted on another forum about my problem... maybe this will help... ? As far as Jeeps go, this guy seems to know his way around the engine. I dont think ive ever learned so much in 2 hours then i did watching him test my engine. Oh, and he fixed my A/C to!

" ok guys,
the OP just left here after a couple of hours of wrenching.
scanner was giving a code P0301, cylinder #1 missfire.
looked at #1 plug, and decided to get new cap, rotor, wires and the correct champion plugs. all plugs gapped @.035.
after a little running, got the same code!
i swapped my injectors to ford motorsport injectors a week ago and kept my old injectors, so installed one in #1 cylinder.
the old one looked like crap after 150k miles.
after a run up the road, it threw the same P0301 code again!
did a little more rooting around, wiggling plug wires and so on. all plugs are now getting a good spark, so i doubt any ignition issues.
also tested the injector plugs with noide lights, getting a good pulse at the iinjectors.
unplug an injector while running and there is a slight change in engine pitch.
when he left here, all was well so i am hoping we did cure it, but i am dubious as it started acting up after the first time round.
when it acts up, the idle goes from 750 to @1000 rpm's. vacuum was between 16 and 27 in hg. so good vacuum i think!
time permitting i would haev pulled the plugs and done a comp test, but they had a long drive and low comp isnt an "easy fix" so i didnt bother with that.
he did say that it felt a LOT faster on acceleration now, no doubt due to new plugs, leads and so on.
any other suggestions for him, assuming the issue comes back as it did before?
again, the code was P0301.
it is bugging me, as i feel bad when someone drives out of my driveway not fixed!

cheers
martin"

" jonathan,
a pleasure having you and your better half around mate, you are welcome anytime!
sorry to hear the cel showed itself again. if it is running good going down the road, i would roll with it and see what shows up when you get back home.
i doubt it is the coil (its a 1998), as it is always showing number 1 cylinder is misfiring. maybe someone can chime in if a bad coil will show itself as number 1 misfire????
the elevation should also be a no go, as the ecm will learn a whole lot quicker than that! i spoke to a friend of mine, and he is thinking the ecm itself, but i wouldnt go down that road until all over avenues have been explored.
try to get the codes read and see if it showing P0301 again. if so, i think my next step would be a compression test across all cylinders. all that involves is removing the plugs and the power wire to the coil, and cranking with the gauge hooked up to a cylinder until all have been tested. it should show a pretty much even number across all 6. i do have the compression tester, but it was getting late after doing the ignition and injector!
keep me posted, and have a safe trip home!

martin"

" no problem jonathan!:thumbup:
i would have liked to do the compression test on it, but time was short.... it was 3am before i got parked up last night as it was!
i dont think head gasket myself, as there was no pressurizing of the coolant etc. when the 4.0 head gasket goes, it will normally blow coolant out, dont ask me how i know that:bawl: that was on a 91, but basically the same 4.0 h.o. motor.
it was also reading pretty good vacuum to have a head gasket leak IMO. but i have been wrong before, too many times to count!
keep me posted, this has me kinda stumped too mate.
say hello to karen for us.

martin & cheryl."
 
Back
Top