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#466 of 1888 99 Wrangler lunging while driving
Sep 04, 2006 (7:18 am)
Hi, everyone. I own a 1999 Jeep Wrangler Sport (stick shift) that has about 62,000 miles on it. In November 2005, I noticed that there was a slight lunging when going up a steep hill (like someone driving a stick that doesn't know how to drive a stick)in third gear. The problem was intermittent and not very bad so I didn't think much of it. However, by June, the problem had gotten so bad that it was occuring just about everytime I was driving and the severity of the lunging was getting worse. Normally it would happen in third gear. The Jeep would lunge felt like it wasn't getting enough gas. If you would hit the gas pedal to floor it, it would barely move. The only thing I could do to get it to stop lunging was to pull over, shut it off and let it sit for a minute. Then when I started back up, it was fine.
Took it to a Jeep dealership in June and they said it was the spark plugs. Took it to another mechanic and they said the same thing and changed the spark plugs. The Jeep did run a lot better, but I could still tell there was a problem. I took it back in, they said they didn't see a problem and gave it back to me.
This past week, I was on vacation and the Jeep sat for a week. Took it to the grocery store yesterday and it was fine. On the way back, got into third gear and it started lunging again. This time it was so bad the only way to stay on the road was to ride the clutch. Finally got to a place where I could pull off and shut the Jeep off, let it sit for a minute, started back up and drove home without any further incident.
It seems that the Jeep does this when I drive somewhere, let it sit for about an hour and then start it up again. The lunging is so bad it's dangerous because you don't have control of the Jeep to get it going, it just wants to stop.
Yesterday when I pulled off the road, I put it in neutral with the parking break on and the RPMs were going nuts in idle. It was hovering around the number 1, but would go up and down and make a rattling noise in the hood.
Someone please help.....my husband keeps talking about getting rid of it! I am REALLY hoping someone can make some suggestions. I have read that it could be the crank sensor. Does anyone have any ideas? PLEASE HELP!
(BTW: I do have another problem with the Jeep. There is a crack in the manifold. It's been like that for years and I haven't fixed it because it's been running fine until now. I don't know if this has anything to do with it or not. The mechanic and the Jeep dealership didn't seem to think so, but I thought I would throw that out there. Any help would be greatly appreciated. Thanks so much.)
#467 of 1888 Re: 99 Wrangler lunging while driving [kelly99]
Sep 04, 2006 (8:48 am)
You need to find a Jeep dealer with competent techs. Your problem could be related to ignition, fuel, a sensor problem, vacuum leak, or any combination of the above. The first place to start is to check if the computer is holding any trouble codes. Just because the check engine light isn't on doesn't mean that no codes are being held.
As for the cracked manifold (assuming it's the exhaust and not the inlet) it could be contributing. On either side of the catalytic converter are oxygen sensors. The second one tells if the converter is doing its job, while the first reveals as to whether the air/fuel mix is correct and allows the computer to correct as necessary. A cracked exhaust manifold can allow air to be sucked in (as well as blowing exhaust gases out) and this will trick the sensor into showing that the mixture is too weak, which will be then be incorrectly compensated for, making for an overly rich mixture which can cause your symptoms.
#468 of 1888 Re: Jeep Noise from the Engine [jvpr]
Sep 04, 2006 (8:06 pm)
I Have the same problem, only my jeep is a 2005.. what was the outcome?
#469 of 1888 Re: Jeep Noise from the Engine [tjbob]
Sep 05, 2006 (3:27 am)
I have a 1998 Wrangler Sahara doing exactly the same thing. I have ran into dead ends with all the garages and self-diagnostics that I have tried. If anyone has the answer, let me know please. It gets really frustrating, and seems to be getting worse. Thanks
#470 of 1888 Re: Jeep Noise from the Engine [tjbob]
Sep 05, 2006 (5:29 am)
I Have the same problem, only my jeep is a 2005.. what was the outcome?
Is it still under warranty? What does the dealer say?
#471 of 1888 Re: Jeep Noise from the Engine [saharasteve]
Sep 05, 2006 (5:37 am)
Maybe you just need to let an older tech listen to it. Years ago it was common to hear big end rattle, mains rumble, wrist pin tap, cam follower crack, cam bearing screach, timing chain jingle, etc., etc. These days, with most engines outlasting the life of the vehicle, it's rare for a tech to hear any of the above on a regular basis.
It should be easy to identify the noise just by listening to it, and without any disassembly being required. Just find an old guy with an interest in old cars.
#472 of 1888 Re: Jeep Noise from the Engine [mac24]
Sep 05, 2006 (7:12 am)
It is still under warranty, went to 1 dealership they said it was normal... dont believe them, i have driven in other jeeps before and they do not have the ticking sound when accelerating. Going to take it to another delaership in the next few days. Here is some other information i have found on the net regarding this problem.
"Looks great. Had it for one week and the motor started ticking. Dealership found metal shavings in the oil, so far this is day 3 without my brand new Jeep. Don't know when I will get it back. Rides well, nice interior."
"What would cause a constant ticking sound in a Jeep Wrangler engine?
Detonation....Needs to be fixed immediately "
"Also, many owners complain of pinging - also known as detonation, caused by fuel igniting before the spark plugs fire - in six cylinder engines."
#473 of 1888 Re: Jeep Noise from the Engine [tjbob]
Sep 05, 2006 (7:49 am)
See my previous post re: older techs. The most common ticking or tapping problem associated with the 4.0 I6 is related to the cam followers, though I'm not saying it's the case with yours.
#474 of 1888 Re: 99 Wrangler lunging while driving [mac24]
Sep 05, 2006 (9:34 am)
Thanks for the input, Mac. You really seem like you know what you are talking about. I did make another appointment for the Jeep and they are going to look at it on Thursday. When I drove it to work and home for lunch today, it was fine. My dad suggested that I should start it and let it run for a few minutes before I go anywhere so I started it a few minutes before I was ready to go back to work.
Now, get this.
I go back into the house and I can hear the Jeep outside. It sounds liks someone is sitting in the Jeep, revving the engine HARD. It goes from that extreme to choking out and almost sounding like it's going to shut off, but it doesn't shut off. It just sputters and keeps going. This is all happening while it's sitting in idle with the parking break on.
I go outside and turn the Jeep back off. The air outside reeks of gasoline.
So there it sits in my driveway. I had to take a different vehicle to get back to work.
I wanted to relay this information to you to see if this gives you any more of a clue about what is going on with the Jeep. As I said, I'm taking it in on Thursday (provided we can get it there), but would like to know your thoughts before I go see yet another mechanic.
Thanks so much,
#475 of 1888 Re: 99 Wrangler lunging while driving [kelly99]
Sep 06, 2006 (3:53 am)
Let me know what you find out. My 98 is doing the identical same thing, down to the exhaust leak on the manifold. I've changed a lot of things. The one thing that may have helped,(time will tell) is that I changed the Crank Position Sensor last night. This problem started a couple of months ago and has been gradually getting worse.