it all started when the truck almost stumbles at idle, i figured the throttle body is gummed up so i sprayed half a can of carb cleaner into the tb while trying to keep the revs at 3k rpms,making sure the carb cleaner doesnt get into the small inlets south of the tb. i reconnected everything up and now it idles at 1500rpms, i tried the ecu reset and ecu idle releard procedure but it still gets to 1500rpm the next time i start her up.
i have alredy removed the whole tb thinking that i might have moved some gunk into the inlets, cleaned it out even the isc, checked for continuity all is ok. connected everything back, still at 1500rpms.
when i remove the connector to the MAF though, the idles drops to a steady 1000rpms, and stays there even if i turn on the a/c. but when i reconnect the amf it shoots up to 1500rpms. theres no ECM or MIL light if the maf is connected.
as i understand from the workshop manual, the idle is controllled by the electronic throttle servo together with the isc, it looks at figures from the a/c load switch and the engine temp sensor and then compares it to a MAP or table with predetermined values. so i know the throttle servo is working because this also looks at the pedal when in drive and adjust the throttle plate to how deep i press the pedal. now im guessing it might be the engine coolant temp sensor or maybe the MAF?
if i disconnect the maf then everything almost idles fine ~1000rpms (normal around 750)
how do i check if the maf is defective if i dont have a known good one to swap it with. and btw upon inspecting the throttle plate, it has a gap between the throttle body, around less than a mm, is this normal or should it be fully shut?
