Question about 1999 Jeep Wrangler

2 Answers

99 jeep wrangler 4.0 backfires and hesitates

My jeep backfires like crazy power goes in and out with constant idle changes in the first quarter mile, then with flooring the vehicle it goes away, leave the car for five minutes and it starts all over again. The jeep has been in and out of dealers no code comes up, just put a new exhaust maniforld on it same problem, anybody with any answers out there thank's

Posted by on

  • 1 more comment 
  • jeepsi Jun 26, 2008

    have the same problem with my 1998grand cheerokee

  • merlars Oct 02, 2008

    I have the same exact problem with my 99 wrangler.  Once the engine warms up it quits, but as soon as its off and cools down it starts all over again...whats up?


    Thanks

  • amestr8 Oct 08, 2008

    I have the same problem only sometimes it doesn't do it at all. No codes come up on scope. I had a similar problem with my 2000 Dodge Dakota, replaced cruise control sensor and problem disappeared, this is my next step with my 1999 Jeep Wrangler. I have already replaced coil, plugs and wires-no difference, it was suggested, that I check gasoline pressure that it should be in the 30-40 psi range.

×

2 Answers

  • Level 1:

    An expert who has achieved level 1.

    Mayor:

    An expert whose answer got voted for 2 times.

  • Contributor
  • 1 Answer

Fairly common problem. Typical scenario is start vehicle, runs fine for 15 to 30 seconds and begins to backfire when placed under load as customer tries to drive vehicle. Flooring usually makes the problem go away. Usually does not throw a code.

Fix is to replace the upstream 02 sensor.

Posted on Jan 10, 2009

  • Officermick Nov 04, 2010

    My 1998 Wrangler 4.0 has the same symptoms. Did replacing the Upstream O2 sensor remedy it? And, does it have much impact on fuel consumption while on the freeway?

×

  • Level 2:

    An expert who has achieved level 2 by getting 100 points

    MVP:

    An expert that got 5 achievements.

    Sergeant:

    An expert that has over 500 points.

    Champion:

    An expert who has answered 200 questions.

  • Expert
  • 393 Answers

Have the idle air control valve/air bypass which ever it has, checked,. look for a vaccum leak

Posted on Nov 16, 2008

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

My 99 alero GL runs great...85,000


COULD BE GROUND PROBLEMS OR THE TACH GOING BAD.EVEN THOUGH CAR SEEMS TO BE RUNNING GOOD IDLING GOOD.SOME TIMES A SPARK PLUG MISFIRE.CAUSING A LITTLE ROUGH IDLING CAUSING TACH NEEDLE TO GO CRAZY.I SEEN ALTERNATOR WITH VOLTAGE REGULATOR GOING BAD CAUSE A POWER SURGE CAUSING HEAD LIGHTS TO DIM A LITTLE THEN BRIGHT WHILE ENGINE IDLING.THIS WILL CAUSE TACH METER NEEDLE BOUNCE AROUND ALSO.

Apr 03, 2010 | 1999 Oldsmobile Alero

1 Answer

1994 jeep wrangler 4.0 idles fine but when traveling cuts in and out and backfires when accelerator is pushed, i do have a cold air intake and jet performance module just recently added


1994 Wrangler with 200,000 miles on the odometer. Similar problem here: Severe bucking and backfiring, and engine misses when traveling down the road. I did an entire tune-up (plugs, wires, distributor, distributor cap, and ignition coil), but got the same thing. I thought it was dirty fuel injectors, so, I poured a bottle in a few times on fill-ups. The final solution, was a bad alternator. My mechanic said it was sending voltage spikes to the computer, causing the engine bucking and back-firing problems.

Feb 21, 2010 | 1994 Jeep Wrangler

2 Answers

Jeep wrangler 2.5. Motor idles up and down,


check the throttle possioning sensor on the throttle body that can cause alot of things

Jan 16, 2010 | 1995 Jeep Wrangler

2 Answers

I've owned two 1997 Jeep Wranglers and eventually they both shared a common problem of rough idle, low fuel mileage, check engine light and and rough acceleration. Sometimes it would run fine but sometimes...


Hi,
This is a broad spectrum of possibilities. I would first start with a simple approach of insuring good gas.
When these symptoms occur, get a bottle of fuel additive and add to your tank. Possibly you have some condensation issues. This could be just the ticket... I hope so. Good luck.

Oct 23, 2009 | 1997 Jeep Wrangler

1 Answer

1990 Jeep Wrangler: Dies out at low RPM's, at stoplights,backfire


It sounds like an intake air ( vacuum ) leak, or ignition timing. Was it doing this before you changed all the above? Or did it start after?
Check all the intake mounting bolts, and carb bolts for tightness. Use a lenght of fuel hose against your earto listen for leaks while the engine is running. A hissing sound will be heard if it's leaking. Wiggle all the hoses with the engine running. You might get lucky and make one hiss at you. A soapy water solution will also detect leaks. ( use hot).
It also could be a leaking egr, or plugged pcv valve, or air filter clogged, or leaking head gasket, bad timing chain, or your camshaft lobes could be worn.
You'll just have to keep looking, and stay calm. It'll feel good when you find it!

Apr 24, 2009 | 1990 Jeep Wrangler

1 Answer

Oil pressure for my jeep 2002 wrangler


As long as it's not going down, and the engine isnt knocking, you do not have a terrible problem. I have used marvel oil in ones that do this and most times it clears up. If not, change the pressure switch. (Takes a few days before it get's better with mm oil)

Apr 22, 2009 | 2002 Jeep Wrangler

2 Answers

Backfiring and loss of power


'till you do some in depth testing of all systems, I'd place equal weight on every possibility. Make sure you cover the basics like fuel filter etc before getting crazy with it though. Also check cap. rotor, coil and wires. Idle cylinder pressure is different than that encountered when driving. This additional pressure will cause ignition spark to seek a better easier ground,(not the spark plugs where it should be going) causing missing under load.After checking , if you haven't found anything, its time to begin testing fuel pump pressures, modules and controls.
good luck

Feb 10, 2009 | 1994 Jeep Wrangler

1 Answer

99 wrangler 2.5 hesitation


If this is hesitation and unsteady idle, check for vaccum leaks at the intake with starting fluid. Frankster016

Jul 17, 2008 | 1999 Jeep Wrangler

1 Answer

99 jeep wrangler


how many miles down your TJ have?

backfire through exhaust or the intake manifold?

I would check:
1. 02 sensor
2. clean the throttle body thoroughly by decarbonizing it as well as cleaning the IAC and TPS.

what was done from the tune-ups?

Jun 22, 2008 | 1999 Jeep Wrangler

Not finding what you are looking for?
1999 Jeep Wrangler Logo

1,976 people viewed this question

Ask a Question

Usually answered in minutes!

Top Jeep Experts

yadayada
yadayada

Level 3 Expert

61249 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

21949 Answers

Jeff Turcotte
Jeff Turcotte

Level 3 Expert

6812 Answers

Are you a Jeep Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...