I just noticed today that when I shift my automatic transmission '99 Cherokee into reverse that it starts stuttering and bucking and hesitating as if the fuel supply is getting interrupted. It doesn't do this while idling or when shifted otherwise, only in reverse.

My local mechanic just had to do a lot of work on it to hunt down an AC leak, including taking the dash out and finally finding a small leak in one of the hoses. I'm wondering if this has anything to do with it - that he might have inadvertently shifted something around, like a ground wire, that created this problem.

In searching around, I found a couple posts suggesting that when the problem is solely in reverse, it could be that the engine shifts so that a ground gets created where it shouldn't when the engine is shifted to reverse that doesn't happen when it's shifted otherwise. Can anyone comment on this and potentially point me to some likely culprits that I can check tomorrow?

I don't think it's the fuel pump or filter or fuel contamination since it doesn't hesitate or stutter when in idle or shifted anywhere but reverse.

Any help is greatly appreciated - thanks.
James

 

I had a similar issue, and my check engine light would come on, but only in reverse.

CEL indicated IAT, but that was not the issue.

The issue was exactly what you found. I traced my wiring harness from the IAT and found that it was touching the engine block. It was ultimately shorting the wires, and when I went in reverse, it would cause the touch and short, then the stumble and CEL,

So check your engine wiring and make sure it not rubbing up against the hot engine and causing a short in one of the wires (map, iat, etc).

 

This^^, and also check your engine mounts and bolts holding engine to trans.

 

Alright, thanks to you both. I'm hoping it's the wiring and not the engine mounts.

 

I'm going to try to deal with this in a couple hours. I don't have the ability or a store near by to check if there's potentially a code getting thrown. Until I can do that, given the symptom of bucking in reverse any particular wires on the harness I should be checking? Thanks again.

 

If you are not getting a cel you don't need to put a reader on it. If the mechanic was trustworthy you might tell him what you found online and he may be able to make short work of the problem.

 

Alright. I took it to the mechanic he tuned it up and replaced an ignition coil and this seemed to help but it started again and then even in forward. It would be particularly bad on bumps and on right hand turns. I looked under the hood while someone shifted it to reverse and the engine tilts in the same direction as it would when going around a right hand turn. So I look and look and finally found what you all were predicting



So after a lot of dinking around, this was the problem. I thought I would post the picture since it seems like this could be a common problem. It's the bundle that is just off the firewall and passes over the fuel rail. The seam got shifted so it was in direct contact with the rail and melted a hole in the insulation.

Thanks to you all.