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Hey guys, have seen and heard a lot of good things about this forum, and was hoping to garnish some clarification on a problem I’ve been having recently.
Background Info: Car is a 1990 Dodge Grand Caravan SE, with a 3.3l V6 and a Chrysler Ultradrive automatic transmission (one of the earliest models, if I’m not mistaken); it has 195k miles on it, and is equipped with Air Conditioning. About nine months ago, I had the transmission rebuilt, before which it sat for a few years. Recently took the van on a short-distance vacation (roughly 250 miles one way). Before this vacation, I drove the van to and from work every day, totaling about 30 miles, without issue. On the return leg of this vacation, I began experiencing what I initially thought was a bad clutch(or bands, or whatever the correct term is, not quite sure), causing the transmission to ‘fall out of gear’. After getting it home without any assistance required, I was forced to continue driving it to work in the following days. I began to realize that it most likely was not the transmission, because, if a transmission was falling out of gear, wouldn’t that be accompanied by a revving engine? The opposite was happening.
The Problem: The engine idles fine when started up, as smooth as it always has. When the engine is cold, it doesn’t seem to stumble. After the engine warms up, however, it seems to misfire or possibly die momentarily at the following points:
– Starting from a dead stop (e.g. Stop Sign)
– Climbing a hill in a high gear (Low RPM, low torque)
– When throttle is applied swiftly (Passing, merging, etc.)
– Occasionally stumbles at highway speeds (65mph in my state)
The stumbling can range, depending on the day, to a few hesitations within 15 miles, all the way to 20 or 30+ just trying to get to speed on the highway. These stumblings, or hesitations, are characterized by the following:
– Loss of 200~500 RPM
– Loss of acceleration, coinciding to a loss of power
– Bears similarities to engine misfire
– Bears similarities to a dying engine (for a split second)The Solution: Alright, I don’t know what it is, or else I wouldn’t be here. I would like to clarify something; I removed a spark plug and inspected it. It matches the verbal and visual description of a spark plug affected by excessive heat and/or a lean fuel mixture, according to my repair manual. This is what led me to the areas that follow. These are what I can think of, and I need you wonderful people to tell me whether I’m on the right track, or whether I’m way off in left field. I’ve considered the following culprits and their components:
Fuel Delivery System:
– Changed fuel filter
– Used fuel injector cleaner as recommended on bottle
– Tested fuel pressure, and it’s to be within the margin of error for the vehicle
-Changed the lone O2 Sensor and reset ECU
Ignition System
– Changed Plugs
– Changed WiresIf you could point me in the right direction, I would very much appreciate it. I hope I provided all relevant information, and if more is required please ask.
NOTE: The car has never died while driving. Also, the coolant system seems in tiptop shape, and I have experienced no overheating issues. The transmission shifts as it always has. Oil change has been done within the last 2000 miles. I am also shying away from the possibility of a vacuum leak, because of its smooth idle and the lack of any hissing noise in the engine compartment.
Thank you all.
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Is the “Check Engine” Light On? Either Y or N you should start with a fault code scan.
Something else you might check is the wiring harness under the battery for damage or corrosion. I have seen electrical faults there that cause all sorts of weird problems.
I just realized I left that bit of info out and was coming back to edit. 😆 The check engine light is not on (although it was coming on intermittently about a month ago), and I am taking it to my local parts store for a reading tomorrow. I do know that there are certain Chryslers (and by extension Dodges) that can be made to blink out engine codes thru the check engine light when the key is turned in sequence. Using that method I pulled a code for an EGR valve that wasn’t detected as changing air/fuel ratio. That was the only code, and was erased when at some point I disconnected the battery, and has not returned. Will return with more info on codes in the coming hours. I will also scrutinize the wiring harness tomorrow, but I have inspected the engine and surrounding components and have not seen any glaring faults.
Thanks
If you could post the code you had or any new codes that
would be great. check the vacuum line to the egr valve.
also test the egr valve.When you tested fuel pressure what
was the pressure? also when testing fuel pressure did you
pull the vacuum line to the fuel pressure regulator to see
if fuel pressure increased? with the engine running apply the
vacuum to the egr valve.the engine should start to stumble/run bad.
When you changed the plugs and wires.Did the cap and rotor get done?Fuel pump just went out. Yay get to drop the tank! Had this strange feeling it was weakening but local guys told me that wasn’t likely. Anyways thanks for the help. If it’s not fixed after I replace the pump I’ll return!
went thru this with89 new Yorker after replacing fuel pump, next day replacing FP relay..it was fixed…
Relay was problem all along
Well, replaced it :cheer: Didn’t have the widest selection of tools to work with, so it was a bit tedious. Seems to be running fine though, no hesitation or stalling. Seems to be a bit more perky, but that could be psychological. Did the math and the whole ordeal cost only about $225, which imo is pretty good for a new pump, plugs, fuel filter and o2 sensor. I’m happy! I’ll come back after a few days and update on how it’s running. Thanks for all the replies guys, really appreciate it.
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