Iac?
 

alright i replaced my IAC yesterday thinking that was my whole problem here...however nothing changed...but i did not clear the computer (diconnect batt. for over night) should i have dont that? i know with the tps you do that i wasnt sure bout the IAc?

No, you don't need to disconnect the battery. Whats wrong with your car?

welll basically when im driving down the road iv i push the clutch in the car will rev UP...somtimes it will idle at 1800 then after a lil bit goes down to normal...umm the biggest problem that i have is this.. here is an exact senario of what will happen time an time again... i get in my car..turn key car starts asap real quick..i go somwhere car gets good an warm...shut her down and within 15 min wanna go restart it up an leave whereever i went well it will just sit there and crank and crank like it wants to start but wont start until i push the gas pedal to the floor while cranking then it starts and runs fine. and then after the little incident trying to start it is when it gets the screweey idle and the whole idleing up after the clutch goes down without my foot on the gas lol

here is what has been done to the car:
i replaced the intake manifold (cracked thermostat houseing)
replaced throttle possition sensor
replaced IAC but i am about to go take it off and return it to autozone if at all possible with a lil bit of bsing

Humm...are you letting the fuel pump prime before you turn the key?

yea ive tried that b4 but shouldnt i not have to do that after the car has already run like a minute b4...i will have to keep note of that primeing situation a lil closer but yea im pretty sure i usually wait till its done primeing but hypothetically if i am waiting as i am pretty sure i do what else could be the prob

Faulty o2 senors will give a crazy idle when the engine is warmed up, ESPICALLY on fords.

Although, I highly doubt it would cause a hard start. Usually the crazy start is a sign of a bad cps(camshaft position sensor). What year is your stang?

Unlikley, but its possible that the wiring harness to the idle air control is faulty.

Hows your fuel pump? Just another poss. I guess

96 gt...now u bring up the 02 sensors...well when i bought the car the lady said that she had to have one of them replaced to ge the car to run..and that to get the ckeck engine light off i need to replace the rest...well i have yet to do this becuz from what i have heard the o2 sensors wont make it idle wierd just use up a lil more gas but when i check my gas milage im pretty much where it supposed to be so mabe o2 sensors?? this seems relevant to me

ohh, fords are a different story. Plenty of expierence with em, and o2 sensors will causing irratic idle on them. Ive only found that on fords and a few hondas, and thats it. That one old sensor may be causing your problem.

Sounds exactly like the problem I had.

Ford replaced the IAC and all is fine and dandy now.

how does everyone feel about what 02 sensors to buy...some ppl say go straight to ford and buy the ford brand o2 sensors others say save your money and go to a regualr parts store.

I usually just go with bosch. But have no expirence with them on mustangs.

Have U had the codes checked to see what the reason for MIL being on but if you have replaced the IAC i would go with the O2 sensor and it is up to you where u get them i dont think one is really better than the other but that is just me

well...i had my buddy put the computer on it a few weeks ago and it brought up the tps which i had already replaced just neva had him clear the code so had him clear it and havnt had the comp on since then however i was just going on my own instinct with the iac(which i just got home from returning because it diddnt help)

yea i would try the O2 because i am stumped it is pretty much trial and error unless u find somone who is sure

alright im gonna do one sensor at a time over the next few weeks...should i start w/ the ones b4 the cats or the ones after and hhow hard are each of them to get too and i think i have heard about a 02 sensor tool?

start with the upstream (closest to the motor) o2's and do yourself a favor and buy the ford ones. You can get them for half of retail price from fordparts.com. All you need is a crescent wrench to unscrew them.

and its a good idea to replace both at once...they generally don't last more than 60-70k miles

yea i agree start with the upstream they should not be to much of a challange to do your self just be careful with the wires