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Dodgerench
Dodgerench, ASE Certified Technician
Category: Transmissions
Satisfied Customers: 3399
Experience:  30+ years Dodge/Chrysler exp., ASE Master with L1 certification. Driveability/ combustion specialist
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Dodge Grand Caravan: - I can't figure out why my 2001 Grand

Customer Question

HI-
I can't figure out why my 2001 Grand Caravan with 3.3L runs rough when put into gear. The rpms start to fluctuate, it hicupes when accelerating from the stop position but then smooths out quickly. I have replaced plugs, wires, pcv, MAP sensor, IAC, TAPS. fuel filter. I'm not getting any emission codes. Any ideas?
Submitted: 1 year ago.
Category: Transmissions
Customer: replied 1 year ago.
The van has 130,000 miles. It is a automatic with front wheel drive. The idle gets rough when put into drive or reverse, also when air conditioning is turned on while idling. Throttle body has been cleaned.
Expert:  Dodgerench replied 1 year ago.
Hi, my name is Ed. Welcome to JustAnswer!. With no codes and all those parts already replaced, I'd be interested in the state of a particular part of your engine electrical harness. A small section directly below the power steering reservoir (and coil) has issues with shorting between wiring, which may explain your loss of performance, but without codes. This section of harness holds many opportunities for circuit shorting, consisting of a B+ (ASD relay 12v input), a MAP sensor signal, a 5v signal circuit input, a sensor ground, plus all six injector control circuits. Slow leakage from the PS reservoir (plus heat) over time causes individual wire insulation to turn to mush, allowing circuits to short together. Your problem is possibly related to having an injector control circuit shorted to another, double-firing two injectors when it's active. This sort of situation doesn't set a code, nor does it necessarily pose an immediate threat to the PCM (engine controller), but that can change minute to minute. Electrical overload of the injector control circuits can kill the injector drivers, something that you can't fix without a new PCM. So. What I'd recommend is to pull the harness out for inspection. You'll need to remove the power steering reservoir first, then the coil pack. Then lift the harness and peel back the screen-door sheathing that protects it from abrasion, but not from fluid leakage. See if any wires are stuck together, as if glued to one another. If the act of pulling them apart exposes copper... bingo! You've likely got some shorting going on. You can choose to replace the entire harness if bad enough, or just replace individual wires as necessary. The MAP sensor wiring is very sensitive and merits extra care when replacing, so be sure to seal the new circuits with shrink tube that contains a glue that seals off the wire (something you can get from the Mopar parts counter if no where else). Expect a new harness to run close to $350. Let me know if you have any questions or problems. I'll be glad to help. Thanks for writing!Ed

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