PLEASE HELP ME!!!!!! 96 ford ranger weird idle issue

[gregnewbert]

any help would be a big help... got a 1996 ford ranger 2.3l manual. about 2 months ago i change out the IAC and TPS because of a weird idle problem. turns out it was vacume line. i figured i would just keep em in anyway. trucks running fine, then i let it sit for a month and now it starts and stalls, and when i manage to drive it without stalling it revs up to about 3 grand without me touching the gas pedal. I checked it for codes and it pulled up p1121 Throttle Position Sensor Inconsistent with Mass Air Flow Sensor, so i changed mass air flow sensor figuring it wasnt the tps because it had a brand new one in. i keep going back and forth with this thing. I need help. Again, the symptoms are no idle at start,then when driving shoots up to about 3 grand inbetween gears...

[corning_d3]

While it was sitting, did the battery run down?

[gregnewbert]

no i doubt it not only does it have a new battery but a new alternator.

[corning_d3]

Hmm, sounds like you may still have a vacuum leak somewhere. Does the brake pedal feel harder than normal? Using more fuel lately?

[gregnewbert]

I couldnt even tell you about the brake pedal it was my buddies truck when i did all the work to it and he just gave it to me.. I hate finding air leaks, whats the easiest way to find em?

[mtmaurer8ooo]

I find the best way to find vac leaks is to, with the engine running and preferably somewhat cold, LIGHTLY mist the vacuum lines and anywhere else it could be sucking air with some carb cleaner. SIDE NOTE! Don't light yourself or your engine on fire...which you shouldn't...but just be careful. If the engine idles up when you shoot a certain part, you may have found your culprit. My suggestion, check the intake gaskets too. My father has a 97 that had a similar issue. We tried an IAC, had it scanned...the whole 9 yards...and it ended up having a bad intake gasket. Let us know what you find. MM

[gregnewbert]

i just sprayed every possible spot i could didn't make a difference... i think im going to try another tps adn see what it does... Also, the gas has been sittin for like a month, would that make any difference?

[gregnewbert]

I just sprayed the crap out of it and nothing happened. I'm going to try another tps, could it be bad gas?

[corning_d3]

I doubt bad fuel is causing the problem, but I wouldn't rule it out. It is possible you bought a faulty TPS..

[gregnewbert]

I just disconected the tps wiring and started it up... it ran 100x better, so im guessing it is a faulty tps but will it make a difference if i put a new one in rather then jus leave the frekin thing unplugged... It started and ran at about 1300 to 1500 rpm's then dropped down to bout 800-850. You guys think its the tps then?

[corning_d3]

Yep, sounds like the TPS. Don't leave it unhooked, just go get a new one.

EDIT: you can leave it unhooked until you get a new one..

[gregnewbert]

thats what i meant haha im not that cheap..

[gregnewbert]

alright.. so the idle problem is fixed. im pickin up a new tps tonight, but the thing is when drivin it it still shoots up in rpms to 3 grand in between gears. Is that because i havent changed out the tps yet or what?

[12Ounce]

I think, to run faster the engine must get "more air". A vacuum leak will give you more air, but you say you've checked that out pretty well. The TPS won't give "more air" unless somehow its affecting the closing of the throttle plate.

Does the throttle plate close as it should? Or has somehow the throttle plate stop screw been "toyed" with? The plate should almost, but not quite, completely close against the throttle body. If held up to the Sun, you should barely see a corona of sunlight around the plate.

After assuring the throttle plate is correct, ... and there are no air/vacuum leaks ... that only leaves the IAC valve... it's function is to control air flow when the throttle plate is closed.

[corning_d3]

Originally Posted by gregnewbert

alright.. so the idle problem is fixed. im pickin up a new tps tonight, but the thing is when drivin it it still shoots up in rpms to 3 grand in between gears. Is that because i havent changed out the tps yet or what?

More than likely, yes. Don't be suprised if it still does it for a few days after changing the TPS. If it continues, unhook the ground cable, turn on the headlight switch and let it set for 10-15 min. Then shut off the switch and hook the cable back up. Start it and let it idle until the RPMs level out, then take it for a spin..