For a long time, I have had a problem of periodic roughness in our '93 JGC V-8. When it occurs, it "seems" like there is a slight loss of power in the engine at the same time. At other times, the engine runs smooth as silk and seems to have plenty of power. I have had the plugs, wires, dist. cap, etc. changed with no real improvement. It's almost like it is running on 7 cylinders when this happens. At least that's what it feels like. What else could cause this?
Dick
Dick did pass the time by typing:
quite a few things, what fault codes does it have?
- how old is your fuel filter?
- how cruddy is the throttle body and the idle air passage?
- how old is your O2 sensor?
- checked the battery terminals and connections?
but first get the codes.
I don't have a scan tool, but the self test codes are 12, 34 and 55. None seem to be related to problem. Fuel filter was changed at
64,000. O2 sensor is original as far as I can tell from maintenance records. Battery and terminals are perfect. Don't know about the throttle body. Injectors were cleaned at 35,000. Jeep has 90,000.Dick did pass the time by typing:
12 - not an issue, just the battery having been off sometime in the last 50 starts 34 - An open or shorted condition detected in the Speed Control vacuum or vent solenoid circuits. Speed control switch input below the minimum acceptable voltage. 55 - end of codesSo, 34:
The speed servo uses the common engine ground. So, you could have a problem with the engine ground strap or the battery to frame ground jumper. Is the hiccup occuring when you have cruise control on (even the button in even if you haven't pressed set).
Another thing to look at are the engine mounts. These are for the I6 but the idea is similar. Shot motor mounts will make the engine run rough (or at least make it act that way)
I know the battery ground is good. It was changed recently when a new battery was put in. I also depend greatly on that connection for my ham radio installation. Engine and trans mounts were replaced at
82,000 miles. Problem just comes and goes with no apparent relationship to anything. Doesn't matter if cruise is on or off, but more noticeable with it off as you have your foot on the throttle.Dick
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