CHECK ENGINE light & RPM increase
 

My 94 Ranger 3L V6 has 285,000km on it. Believe it or not everything worked fine until about a week or two ago when I noticed something strange happening. When traveling on the freeway at about 50mph the RPM's suddenly shot up from 3000 to 3500 without any increase in my road speed, simulteanously, the CHECK ENGINE light turned on. After about 10 - 40 seconds the light turned off and everything returned to normal. Since than, these symptoms have repeated on a more frequent basis, and the duration of the symptoms are prolonged. These symptoms only apear after the engine has warmed up. Once the engine is warm (i.e. 20-30min. of driving) the rpm's act up even at low speeds. I was just wondering what could be causing these problems.
- - CATALYTIC CONVERTER??
- - SENSORS?? (speed..idle..cruise control..etc...)
- - TRANSMISION??

p.s. - i'm not sure, but i think my truck slows down a bit, when this happens, and it requires extra acceleration to maintain the speed.

Please help.

RE: CHECK ENGINE light & RPM increase
 

Sounds like your overdrive solenoid in the trans is disengaging while driving. Now this could be for a couple of different reasons, one being a faulty solenoid in the trans, but also, the PCM looks at engine temp to determine if it is hot enough for the lockup convertor to come on. So that is one thing to look at, another would be the harnass going down to the transmission. A break or poor connection could cause this. You need to have the trouble code memory read to determine if that is, in fact, the problem you are having. [sm=mail.gif]