Posted: 3/14/2004 2:34:44 PM EDT
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I had a strange problem in my vehicle, Mits montero sport, v6 3.0 4wd AT. I first noticed the problem on my way to work one morning; accelerating up the freeway onramp the engine started cutting out. Let off the gas and resume throttle and it was ok if you didn't push it. After driving it and noting the conditions it occurs under I nailed it down to the following. When accelerating from a stop, the engine will wind up normally and shift into second gear btween 4-5000 rpm. Pulling in second it will hit 3400 rpm and that is it. You can keep the gas pedal on the floor, shift into neutral and the engine will putt along at 3600 rpm. Let off the gas, it resumes normal operation. It does ok on the freeway, when you are accelerating if it acts up you just let off the gas and push it again slowly. Since the engine runs at 2700 rpm at speed (just they way its made, the 3.0 is too small for this vehicle) it pulls along fine unless you really get on it or climb a hill. I figured that the consistent rpm and transmission gear behaviour made this a computer issue. I called the dealer and they said it could be one of a dozen things and they wanted $90 just to pull the codes. (no engine light, no transmission indicator). Called another shop, same price, so I rented a code reader and there were none. BTW, if someone can explain why I can pull codes with key on engine off but not with key on engine running I would appreciate it. Whatever was happening was something the computer considered within its normal operating conditions and therefore had to be a problem of bad input or a sensor. At point I put on the thinking cap. I knew the engine is equipped with a speed limiter and it was meant to keep you under 30 mph if you were in 4low to prevent transmission damage. But I wasn't in 4low and I was able to drive at unrestricted speeds, just not unrestricted rpm's in upper gears. I did figure out was going on and made the problem go away but I want to see what you all come up with before I post it, maybe later tonight. |