high idle

[Dave the dude]

I have an 89 D50 4X4 that I put a 3.0 V6 in. It runs great but when started, it idles up around 2k until it gets warm and then comes down and idles fine. However sometimes I will be driving along and it starts to idle high while it is at operating temp. Sometime it takes a while for it to idle properly. Any ideas? I replaced the temp sensor and had the computer rebuilt when I rebuilt the engine.

[camoit]

How about the high idle solenoid. The one that kicks up the idle for the AC. I think it makes a vacuum leek to do that. I may be wrong. The other guess would be a sticking cold start injector or something along those lines. Or the MAS is doing something strange. How is the fuel mileage since it started doing this?

[Dave the dude]

It has done it from the start. After I rebuilt the engine it would rev wildly high to low until it warmed up. That is when I replaced the temp sensor. That stopped it from doing that but it has always done this other thing since. Fuel economy is a steady 19 which is acceptable but not great. Don't know what I should be getting with this engine.

[lush90]

I have a '90 and a '91, both 4x4's with 3.0 V6's and I'm always in the 17-20 mpg range. It doesn't seem to matter if they are running empty or hauling a ton of stone, the mileage is very consistent. My all time best was on a trip keeping it right at 60 mph and I got a whopping 21 mpg!

[Dave the dude]

Thanks Guess I'm doing o.k.