Questions and Answers

Dodge Dakota Broken, Fine Now Q. 1989 Dodge Dakota, V-6, 3.9 liter, fuel injected, automatic transmission, 107,000 miles. I am the original owner, and have driven it countless times from Phoenix (1200 feet. elevation) to a cabin in the White Mountains of Arizona (8,000 feet elevation) and have never had any problems.

I made a trip recently, no problem going up. The next morning at the cabin (50° air temp) when I started it, the engine surged from about 1,500 rpm to maybe 200 rpm and then back to 1,500 rpm and continued to cycle like this. Engine would nearly die at 200 rpm. I took it for a five mile trip and it bucked continually. I thought perhaps it was starving for fuel, and replaced the inline fuel filter. It seemed to run okay, (engine warm) and I thought I had solved the problem.

Over the next couple of days I found that the truck would stumble and buck during engine warm-up, but ran okay after the engine was at operating temperature. I got it into a garage at Springerville and a diagnostic check showed no code faults. During further checking, they replaced the distributor rotor, and replaced the temperature sensor, and I drove it around with everything working okay (engine warm).

Next morning, same problems. Got it back into the garage and left it with them so they could have a cold start the next morning and maybe find the problem. They said the engine "went crazy" when they started it, and they went through the diagnostic checks with the readout, still no code faults, and then spent several hours trying to find out what was wrong.

The next day the owner of the garage said they were stumped. He thought the truck would run okay for the trip back to Phoenix since it ran okay when the engine was hot, so I drove it back (220 miles) with no problems.

Now, since I have been back in Phoenix, the engine has performed normally. I have had no problems during morning start-ups (air temperature about 80°) and it has run fine around town (max air temp about 110°). I am reluctant to get it into a garage here and spend another healthy hunk of change since it is running fine.

I have spent some time at the library studying a 1989 Dakota Manual, and I am wondering if the O2 sensor or Hall Effect sensor could be the problem. I had discounted the change in barometric pressure, but maybe I am missing something. If you can help, it certainly be appreciated.

Thank you,
Lee

A. This will be a very difficult problem to locate if we can't duplicate the condition. Without codes there is no starting place to look and since it is fine now, everything we check will check out good.

The mechanic did the obvious by replacing the coolant temperature sensor (and hopefully not the coolant temperature sender for the dash gauge).

I would have to say at this point, since it is running well and there is no MIL on or codes stored, not to worry about it. Having it tested now would be a waste of time and money. I would wait until the symptoms can be duplicated before doing anything.