1999 Jeep Cherokee is sputtering, throttle surging and back firing

Last year the 1999 Jeep did the same thing. Took it to the mechanic and they said it was the throttle control value. They also replace the spark plug wire and plugs with a turn up along with the throttle control value.. The Jeep ran good for a year, then started doing it again. When you start the Jeep up it runs good for about 30 seconds then it run real rough. Clears up for a few minutes, then when its totally warm, it runs rough again. Took it back into the shop and they said nothing showing on computer read out. They said they dont know whats wrong maybe its the (Brain Box) but they are not sure. Told us to take it to a Jeep dealer. Any suggestions or help would be very appreciate before I go anywhere else and lose money :uhoh:

Thank You Gary and Gayle Siler

Reply to
pinkbumblebee
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You just had the plugs and wires replaced last year but how many miles have you driven since then, it may be time for a tune up. You need to find a shop that knows what they are doing. You need to hook up a scan tool that can read sensor values when the problem is occuring. That should allow a decent shop to determine what the problem is.

Reply to
Mike

Thanks you the reply Mike.

Actually we had the Throttle control value replaced last year along with a tune up. It may have to go to a dealership for the value and sensor test. We only put around 15,000 on it last year.

Thanks for your suggestion!!

Reply to
pinkbumblebee

When the throttle position sensor (TPS) gets out of whack on a Jeep, it is normally corrosion on the plug and socket, same for the CPS or crank position sensor. The connection is so shaky on the CPS that one fix is to bypass the plug with a solid soldered or crimped connection.

When your TPS was changed, that only cleaned 'half' the plug and socket combo so it lasted for a little while. We were told ours was dead by Jeep back about 8 years ago. It is still in there after a few cleans of it's connection.

I recommend a spray contact cleaner you get from electronic shops for all the computer sensor plugs on the Jeep. The ones on the throttle body (TPS and idle control valve (IAC)) need it about every two years on ours and it only takes 30 seconds to clean them. WD40 will work in a pinch for cleaning the contacts, but the real stuff is better. I finish with a smear of dielectric grease on the plug's seal skirt.

It is a cheap try anyway.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail > Last year the 1999 Jeep did the same thing. Took it to the mechanic and
Reply to
Mike Romain

And, if the connection ISN'T bad, a smear of dielectric grease will help keep it from going bad.

--scott

Reply to
Scott Dorsey

Scott Dorsey & Mike Romain : Thanks you guys bunches !!!! Im going to print this out and take it to the mechanic and see what they say. Do you think maybe a Jeep dealership would be best? We live in Gulfport, MS and there isnt many mechanics in this city.

We really appreciate your time to help us :)

Reply to
pinkbumblebee

The spray cleaner fix is something I do in the driveway before my wife takes it to work when she complains of bad idle. It literally takes 30 seconds each to unplug the two plugs on the throttle body and give then a quick spray. Nothing is in the way of this, they are right on the front and there are only two plugs on the throttle body.

Even a shot of WD40 into the plug and socket will give instant gratification if the connection was the issue.

I personally wouldn't recommend spending money on this, except to by the cleaner spray.

Mike

Reply to
Mike Romain

Mike: My hubby and I finally got the contact cleaner today and cleaned the sensors.. So far it is running better :) He was out of town for awhile and we finally got to it. We wanted to thank you again!

I really wished we could find a trustworthy mechanic down here. We've had so much trouble with them here.

Gary and Gayle

Reply to
pinkbumblebee

Thanks for the update, hope it holds.

Mike

Reply to
Mike Romain

Could this possably be the same fix for a problem I am having?

The Jeep started smoking and running rough, did a tune up ( Plugs, Wires, Cap and Rotor) and since it has been low idle, not smoking as bad but running real rough, and back firing. Put some fuel injector cleaner in and seems to have knocked out most of the smoking and it is running a little better but still at low idle ( about 700 - 750RPM). When I press the gas and get it to about 900 rpm it runs great. Any ideas?

Thanks

George

Reply to
GaSmokeEater

Yes, a dirty contact on the electrical plug for either the TPS or IAS on the throttle body can do it.

The Idle air control can also get gummed up. You can look down the throttle body to see it, but the connection is the first thing to do.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's - Gone to the rust pile... Canadian Off Road Trips Photos: Non members can still view! Jan/06
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Reply to
Mike Romain

Thanks I will let you know if it worked.

Reply to
GaSmokeEater

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