4wheeldrivenewbie

I have an 89 cherokee and ive replaced plugs wires cap fuel filter air filter oil change iac tps cleaned the throttle body checked the o2 the map sensor the egr all good put on a new vaccum harness still nothing has seemed to work. i just had my exhaust fixed and still i get bouncing idle in park and now as soon as i put the car in driveit doggs right down idle gauge goes all the way to 100 rpm almost the bottom then shoot right back up to about 800 rpm used to do it worse in reverse now im getting it bad in drive and reverse. Before after warm up it would idle fine for 20 seconds then drop down to like 400 rpm then shoot back up to 900 for another 20 seconds then drop down again. Today after having the exhaust fixed it seemed to run smooth at first now its bouncing up and down every 2 seconds while in gear or reverse 900rpm then 100 900 then 100 up and down. ive posted a video so some of you can see it however the video doesnt show the big rpm drop just the car in idle bouncing tac. Any ideas ive had this problem with bouncing idle for awhile now. Id come to a stop light go to touch the petal and it would stalll unless i got on it then it would choke for a second then launch itself. Heres the link http://youtu.be/hwuJhbnsXuA

XJ Stryker

clogged fuel filter?

Whats your pressure at the rail?

4wheeldrivenewbie

Ive replaced the fuel filter last year because of this problem i was just drawing straws the old fuel filter there was nothing wrong with it so i replaced it for nothing. Whats the easyest and cheapest way to check the fuel pressure

4wheeldrivenewbie

http://youtu.be/QtE4P10sLtE Heres video number 2 u can really see it bounce this time

4wheeldrivenewbie

ok guys sorry about the months of annoying non spaced posts but seems no one has mentioned that these jeeps are sensitive to grounds and could cause idle problems etc so i looked into it and this is what i found.

Heres the link to the video. Could that be one of the causes if not my whole problem?

4wheeldrivenewbie

ok so ive replaced the negative battery ground cable it was mostly covered in oil on the motor side and one or 2 wires fraided. and a slight amount of corosion.

cleaned the firewall ground. Even added a body ground from the neg cable to body cleaned both motor grounds and now i seem to have almost steady idle slight if any bounce at 1000 rpm. Now when i put the car in drive or reverse and try n give it gas it dies unless i let it roll backwards with no pedal. When i give it gas in drive or reverse tach drops and the thing dies

Slick761

My problem was dirty injectors and a vacuum leak. Similar symptoms. Oh and try http://www.lunghd.com/Tech_Articles/...und_straps.htm for your ground issues. Talks about tps issue at the bottom.

4wheeldrivenewbie

I dumped some injector cleaner type stuff in about 4 months ago dident seem to do anything and the **** was from a discount store looked unopened then i noticed some black dots in it after using alil of i threw it away. Im thinking of trying some seafoam also someone mentioned putting seafoam in a little bucket and letting a vaccum line suck it up?? which one would that be? what is the best way to seafoam the injectors any ideas?? Also which vaccum on yours was leaking

94JeepCherokeeMan

Lucas fuel injector cleaner or seafoam in the gas tank man

94JeepCherokeeMan

The seafoam intake cleaning is throufh the brake booster line lol

Slick761

Which one wasn't... I would fix one and find another. The very last Ione was at the vacuum ball in the bumper. My map sensor line was broken line to the airbox was leaking. At first it was just high idle... it became fluctuating and now it is good. Check the line to your map carefully. Also those additives wo.t do it. You need to take the injectors out and clean em. I recommend getting the ford or neon Injectors at the junkyard because they are one piece and safer. They need to be cleaned and rebuilt.

Slick761

And like the link in my previous post said it could be the ground coming in to the tps

Slick761

And fuel pressure is easy. You can rent the test kit. You just hook it up where you would relieve the pressure to the fuel rail and fire it up basically

4wheeldrivenewbie

Well i cleaned both grounds other day firewall and replaced battery ground.

I also figured what the heck id waste 7 bucks on some seafoam i poured some in like in the videos.

Nothing i still get a slight bounce in idle. Its not way up and then way down to stalling but it bouncing alil still.

I barely got any smoke with the seafoam which i figured I cleaned everything awhile back At first it seemed to idle better after the seafoam but it did not it just went from 1000 rpm to 1500 rpm every few seconds so i think the seafoam did nothing much.

Now in park not fully warmed up if i go and hit the gas too fast it bogg its self way down fast almost stalling out

94JeepCherokeeMan

Check vac lines