RPM headaches

[madman7]

I took my 91 X for a drive on the highway yesterday, when I came to a stop I noticed that my RPM gauge was reading 1000. Took my foot off the gas and my truck accelerated on it`s own to about 30kph. I brought the truck straight home put it in park and the RPM`s raced up to 2500rpm. I immediately shut the truck off, started it again the rpm`s were fine. I decided to take the truck out today to test it the truck seemed to be fine, at idle it runs at about 700rpm, at 50kph it runs at about 1500rpm, and at 80kph it runs at about 2300rpm. The above problem though only happens after driving at 100kph or better for a while. I`m worried about causing damage to the engine or tranny.Anyone have any answers or suggestions?

 

[Premier]

Sounds like the MAF or MAS. Do a search on how to clean it.

 

[madman7]

Browsing through some of the older threads I came across someone else with the same problem and it was suggested that maybe it might be the TPsensor or vacuum modulator(diaphram) does this make any sense?

 

[Premier]

No.. havent heard of either causing that. There is also the IAC. I would try and clean the maf/mas and iac. See if that solves your problems. There are threads with pictures in them, if you need help locating the sensors.