my '91 3.0 when warmed up idles kinda rough around 600-650rpm, and as expected in the cold 1000-1500. but today i took a 100 mile trip and let the truck sit ten min. i go to start it, fired up quick and then died. did this a few times, then put it in neutral (auto trans by the way),then i gave it throttle once it started n it wanted to idle 500 rpm and wanted to go lower. put in park about 600-700. this is the first time this happened. ideas??

i was told puting in a thermostat may help with rough idle?

thanks much for the comments!

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1991 Ranger 3.0 XLT

not so sure about that. but think about it like this how is something that only controls when coolant goes through the motor going to control an idle problem. try checking the TPS and look for vaccum leaks. thats about as much as i can help you. and dont replace a thermostat unless your truck overheats untill then it aint worth it. if it makes you feel better you can get some coolant flush and system cleaner and give that a try

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Never tell people how to do things. Tell them what to do and they will surprise you with their ingenuity."
General Geroge S Patton
2007 3.0
automatic trans, 4.10s with L/S
ported and polished TB
4brand new speakers with inslation in doors
smoked tail lights
20%tint on driver and passenger windows
5% tint on back window

ya i thought logically the thermostat makes no sense but we'll give it a try. radiator leaks so ill try some bars in it and put the thermostat in then.

when its cold out it idles higher which should be normal, but when its been warmed up after a period of time it idles LOW, like 500 rpm, kinda chuggin. does the computer not think it has to idle high since its warmed up or what do you think?

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1991 Ranger 3.0 XLT

Hey Guys;I don't know what to tell the guys with the newer 3.0s but the older ones with a dist,like my 93,will wear out the dist bushing & cause a rough idle.I replaced mine & she's smooth as silk!