2WD 3.9L 92 Dakota stalling and acting really...wierd...

3833 Views 4 Replies 5 Participants Last post by ka9yhd, Apr 15, 2016

JBowman27

Discussion Starter · Apr 15, 2016

Okay, so, short trips in town the truck does fine. But after I've driven around for about 30-45 minutes it starts to stall like its being starved for gas. 50% of the time if I put the pedal to the floor it'll stay in the ame gear and at the same speed, the other 50% of the time it'll upshift and jump forward like its at Talladega, but it never really quite rights itself, once it slows down it starts to have the same problem again. Then if i turn it off to let it sit for a few minutes, it'll start right up but it wont idle. It stalls out and dies unless i hold down the accelerator. But if it sits for an hour or more it'll start right upand drives fine then the problems persist. I learned on Mopars and have to say, I'm dumbfounded. All filters, fluids, and gaskets have been replaced within the last 600 miles. Also, not sure if its related, but about 10% of the time when i put the pedal to the floor it'll shift a little harder than what I'm comfortable with, but only when its having the stall out issue. So, like I said, I'm at a loss for words. Sombody please help because this is my daily driver. Oh, it's also a Throttle body, not injected or carb'd.

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ImperialCrown

· #2 · Apr 15, 2016

Welcome to Allpar. Diagnosis first. Any fault codes? Do you have a fuel pressure gauge that you can connect and pin under a wiper blade to monitor fuel pressure while driving?
The TBI system should be around 14 psi up to '92. There was a transition to the Magnum TBI and pressure increased to about 40 psi.
Don't forget to rule out ignition system possibilities. Low spark voltage when opening the throttle will 'blow out the candles', so to speak.
You want this to be in 'acting up mode' while looking for the cause. Are the Champion RC12YC spark plug tips a tan/white color?
Is the spark from the ignition coil a nice blue-white and not an orange color?
Transmissions can kickdown harshly with engine torque output issues and open throttle. Get the engine issue solved before judging the transmission.

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valiant67

· #3 · Apr 15, 2016

1992 should be Magnum with MPFI, not TBI.
1991 was the last year for TBI on the 3.9 engine.

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Scrounge

· #4 · Apr 15, 2016

Like IC recommends, check for fault codes first. Do you know the key dance? Key in the ignition, on-off-on-off-on, the check engine light flashes, count the continual flashes between breaks, these will be your fault codes. The last one will be 55, which is end-of-sequence. It reads like a sensor problem: Throttle Position Sensor, MAP sensor, or Idle Air Control Valve come to mind. I think the MAP sensor will return a 14 code and the TPS will return a 24 code. And check the wiring going to each -- I corrected a TPS problem by splicing a frayed wire.

I'm currently having similar stalling problems with my '92 Dakota V6. The connector to the PCM sometimes works loose, and I'll have to push it back in. I'm now in the habit of pushing it in whenever I buy gas, or open the hood for any other reason.

Through the '96 model year, the Dakotas look like they have TBI, but it's actually multi-port.

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ka9yhd

· #5 · Apr 15, 2016

What is the condition of the throttle body? When is the last time the throttle body has been cleaned with throttle body cleaner?

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