Rough idle in reverse

lost1 · Apr 27, 2005

In the interest of a perfectly tuned Jeep (lol...) I'm trying to track down the source of the only real problem I've found in her yet. When I go to reverse, it idles rougher and I can smell something like gas.

Having next to no mechanical expertise (spark plugs and temp/oil/voltmeter guages were huge celebrations for me)
I can only guess that for some reason its burning too rich. I've read that this can happen when the engine's cold, but I've experienced the same thing after 200mi+ trips, and its not as if I'll ver see snow or ice in southern Arizona. ;D

Any suggestions on this? Thanks, lost1

bajacalal · Apr 27, 2005

My understanding is that holding the car in stopped reverse w/ an automatic transmission is putting more load on the engine than stopped in a forward gear since a lower gear ratio is used for reverse. Correct me if i'm wrong about this. Have you tried the basic decarbonizing / good fuel injector cleaner, filters, general tune up stuff?

lost1 · Apr 28, 2005

Yep...got a replacement K&N filter (used, clean, and soon to be replaced by a conical system) inside, new Bosch Platinum plugs and I run cleaners through every couple thousand miles or so. I recently began trying the 4oz acetone trick from aother thread, and I have noticed smoother idle all around. Before, the reverse gear would really make the whole Jeep shudder while I was backing up. Now, it shakes a little at first, smooths a little, and stinks!

JJacobs · Apr 28, 2005

This might sound weird, but check the bellhousing bolts. BTDT.

lost1 · Apr 29, 2005

I'll have to look @ that... but what does BTDT stnad for? :?

JJacobs · Apr 29, 2005

been there done that

bajacalal · Apr 30, 2005

lost1 said:
Yep...got a replacement K&N filter (used, clean, and soon to be replaced by a conical system) inside, new Bosch Platinum plugs and I run cleaners...QUOTE]

Good for you then also I would not neglect the wires/coil. I had a similar situationonce where it would idle bad cold, because one of the wires got water & salt in it and corroded and diddn't fire good. It was bad, but 4.0 is tough and you diddn't notice it after it was running.

lost1 · May 6, 2005

bajacalal said:
lost1 said:

Yep...got a replacement K&N filter (used, clean, and soon to be replaced by a conical system) inside, new Bosch Platinum plugs and I run cleaners...QUOTE]

Good for you then also I would not neglect the wires/coil. I had a similar situationonce where it would idle bad cold, because one of the wires got water & salt in it and corroded and diddn't fire good. It was bad, but 4.0 is tough and you diddn't notice it after it was running.

Click to expand...

You nailed it dude...some crazy corrosion going on in those connectors there...gonna attack it this weekend w/ a wire brush to hold 'er over till I can get some new wiring. Guess the previous owner never thought to do that. *shrugs* Thanks for the tip!

bajacalal · May 7, 2005

You nailed it dude...some crazy corrosion going on in those connectors there...gonna attack it this weekend w/ a wire brush to hold 'er over till I can get some new wiring. Guess the previous owner never thought to do that. *shrugs* Thanks for the tip!

You'd be surprised how fast it corrodes. I drove (illegally) on the beach and trashed the plug wires and coil, it was fine before and I hosed it off in there after. I was actually surprised it was running so well. This was in 2001 and recently the same thing happened again, got all corroded but thats a consequence of going offroad. Also the distributor cap is vented so water and dirt can get in there and I would just go ahead and replace the coil if its corroded and probably fried from high resistance. Let me know if you are having other problems.

Rough idle in reverse

lost1

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bajacalal

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lost1

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JJacobs

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lost1

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JJacobs

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bajacalal

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lost1

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bajacalal

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