Weird Rough Idling

[Skipper51]

Does anyone have an idea of where I can start looking to find out why the Jeep idles roughly. :firedevil
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When it is in park after being and idling for 30 seconds or so it starts idling roughly. Then when put in reverse or drive it starts idling fine. Then when I put it back in park, park not neutral, it start idling roughly again. :helpme:

I have no idea what it could be.

Lisa also said when she had it in 4 wheel drive that acted like it was going to stall and did not respond to the gas peddle being push down that it just idled roughly. :sure:

I know it is not much to go on but if anyone would know what it could be it would be you guys.

All I have done lately to the rig is put Sea Foam in it 200 miles ago.

 

[goodwilljeeper]

On mine if u have the air or heater on it idles roughly like that. But that's probably not helpful.

 

[blondejoncherokee]

Pull the idle air control valve out and make sure it hasn't fallen apart. My rig did the same thing once, and the darn IAC fell apart in its cavity .

 

[Skipper51]

Thanks guys. I think I will clean the IAC valve and see if that works.

 

[blondejoncherokee]

also clean all sensor connections and clean them with some electric parts cleaner, and check for vacuum leaks, intake leaks. you can spray a spray bottle full of water around the intake and vacuum, or carb cleaner, to check for leaks.

I guess its possible the sea foam fouled a plug or a o2 sensor, but I doubt it.

Consider disconnecting the negative battery terminal for 30 minutes to see if just clearing everything helps. and clean the terminals just for fun while they are off.

 

[rocknxj]

I had a cracked rubber vacuum boot at the intake manifold that gave me the same symptoms. Check your vacuum lines physically, or spray starting fluid around your intake and listen for RPM changes.

 

[Skipper51]

Hey Jon I just changes my plugs in Moab a couple of months ago.
Cleaned a very dirty IAC valve and it running pretty well. I will keep an eye on it and see if this fix holds up as being the one that got the job done.
Thanks guy again for your input as I had no idea where to start looking.

 

[blondejoncherokee]

Ya i remember you changing your plugs. I meant if you sea foamed it after changing the plugs, you could have possibly, probably unlikely, fouled a plug in the sea foam process, although I doubt it. A dirty IAC could do it.

sounds like the IAC might have done it!

 

[Skipper51]

Ya i remember you changing your plugs. I meant if you sea foamed it after changing the plugs, you could have possibly, probably unlikely, fouled a plug in the sea foam process, although I doubt it. A dirty IAC could do it.

sounds like the IAC might have done it!

I figured you remembers me changing the plugs. I whined about it then and I was whining about now. I hate changing plugs with that coil bar on them.

 

[EricsXJ]

All the above are good recommendations. In addition make sure the throttle body is clean. The best thing to do is remove it (simple 4 bolts) and clean all black carbon buildup from the inside walls of the throttle body and throttle valve with carb cleaner and a toothbrush.

 

[Skipper51]

You know my throttle body id=s still fairly clean because I had it boared out to 60mm two years ago.
So far cleaning the IAC has solved the problem but I am still keeping an eye on it.

 

[Skipper51]

Well it has been a week now since I cleaned the IACV and it is running well. I think the sea foam is working and might have contributed to the IAC being dirty. Since sea foam works so well I will be using it twice a year to keep the engine clean.
What is your experiences with poring it in the intake manifold and the gas tank? How much for each?

 

[XJensen]

I Let The Brake Booster Vacume Line Suck 1/3 A Bottle Into The Intake Manifold Once. Letitstall Out And Soak For 15 Minutes. Cleaned It Out Real good

 

[Jeep450r]

I used seafoam on my heep and didn't notice any difference. My buddy used it on his 68 Lincoln continental and it helped it idle smoother. Another buddy of mine let it sit overnight in his Saturn sl2 and then smoked out all of down town Pleasanton (main st). Not sure if he noticed any improvements, nor do I care. The smoke show alone was worth it lol.

 

[Skipper51]

Yes after thinking about this I wonder if there is a logical way to use Seafoam. Start by adding it to the tank and the oil then after 500 miles add it to the manifold to keep the junk moving out the tail pipe.

 

[XJensen]

Dont Drive More Than 100 Miles With It In The Oil!

 

[Skipper51]

I have driven 400 already and was told that 500 was the mark. What did I do to the rig driving it the extra 300 miles????

 

[Jeep450r]

What does the can say? I thought it was more than just 100 miles

 

[Skipper51]

From the Seafoam web site "Just add 1 1/2 oz Sea Foam Motor Treatment per quart of oil. The length of time you need to leave it in your oil depends on how much old-oil residue and varnish is in the crankcase. Sea Foam Motor Treatment works by dissolving this buildup and returning it to a liquid state, which will make your oil dirty more quickly than without treatment. Check your oil regularly for color and clarity; when it looks dirty, change it."

 

[XJensen]

That is just what I heard. Check the color of the oil and I would change it asap.

It also breaks down the oil. I'm sure its fine. I just like to be conservative.