Trouble at low RPMs

[KYEdge]

I have a 3.0 2002 Ranger.

A few months ago the oil sending unit was replaced.

Now, whenever the truck is revved to less than about 2000RPMs the engine gets very rough and wants to cut out as the RPMs drop; and the oil guage goes crazy bouncing back and fourth. It happens alot when driving in the city because of stop lights and stuff, but it will do it sitting still if I just blip the throttle a little bit.

Coming into work just now it did it when I was slowing down to stop at a light after turning onto a short street (I turned onto the street, gave it a little bit of gas to get up to about 25mph, drove a block and let off the gas and got on the brakes to stop.) This time the oil guage went crazy, the engine almsot stalled and ran rough longer than it normally does, and the check engine light came on until the idle smoothed out.

Does sound like something common? It would figure this would start up now that the warranty is expired.

 

[99RangerBoss]

i would say its your idle air control valve take it off clean it out with a clean rag maybe oil the plunger then slap it back together and try it again.

 

[rurouni20xx]

try cleaning/new iacv, and have the code pulled and look at it, sounds like you have some kind of wiring issue. another guy on here had problems w/ his revving uncontrollably brand new, said his wiring harness was in a bind somewhere, look at your harness and make sure it isnt against the exhaust or hot valve cover and not in a stress bind somewhere.

 

[betomonroy]

I think the IAC will throw a permanent MIL code and not something temporary. Check Your Spark plugs and look for Reach or lean conditions. But at the same time This can also be triggered by a faulty IAC.
Pull the history codes to see what's in the near past also as well as the present.
This may help.

 

[Wicked_Sludge]

I think the IAC will throw a permanent MIL code and not something temporary.

not at all. sticky IAC solenoids often dont throw codes at all.

i agree have the codes pulled FIRST. most auto parts stores will do this free of charge.

most likely its a misfire code, which probably wont help us much...but its a start.

 

[rurouni20xx]

my iac held my trk at 4k, no mil.