ok has been a gtreat car up to thgis point but i hit a snag....i am more of a truck person myself it is my dads car and for whatever reason just recently he has had problems...if you start the car it wil rev up and then just stall... if you try and hold the throttle at a constant rpm it wil rev up and then bog back down....but if you pulsate the throttle it will hold an almost constant rpm...it almost seems to me like it is starving for fuel....i originallly thought it was a vaccum leak but if it were a significant enough leak then i would think i would hear a loud hissing noise which i dont seem to notice here any input is appreciated.................................


ok

as an update cleaned the iac cleaned up where the egr bolts on...

no luck i dropped some drygas in the tank thinking maybe he got water but didnt help

when you first fire it up after sitting...the idle rolls ...up and down until you pulsate the gas and let it warm up ... then it will chug like an old farm tractor

im leaning toward maybe time for plugs and wires and a fuel filter....

but just out of curiosity would a plugged cat converter cause it to act up like this

if so how could i tell

and checked the saved computer codes and said all systems ok...
..................................................



just as an update... still wont straighten out ... went throught plugs wires,cap,rotor,fuel filter ,air filter no luck this thing is still chugging like an old farm tractor...i also unhooked the exaust and left ity wide open and didnt change anything ....

when you pull up to a stoplight in order to keep it running you have to 2foot it 1 on the gas to keep it chugging and the other on the brake to keep it from crreping along and it surges forward and drops back with the way the rpms jump up and down...

im going to drive myself mentally ill with this ...i also tried putting isopropol drygas and also fresh gas in thinking that he got a batch of bad gas.... but that didnt straighten it out

wondering what is left to check out ....tempted to go to the boneyard and getting a udes tfi distributor mounted module ...and hooking it up to try and eliminate that as the culprit ....

thought about an o2 sensor gone bad and telling the car to lean out the air fuel mix when it isnt needed... but the check engine light isnt on and the code scanner came up with the a-o-k code

when you step on the gas with the car in park it will bog down and give out a popcorn machine sound traveling out the exaust until you have the pedal darn near floored and then it straightens out

seems to be running somewhat hot too

i know i am one of the bigger idiots here on the board but im asking for any H E L P here

 

Sounds like the IAC causing the rolling idle. You said that you cleaned it up, but it should be replaced. First I would do a search on how to clean the MAF. If the mass air flow meter isn't working properly it will show symptoms as you described:
"when you step on the gas with the car in park it will bog down and give out a popcorn machine sound traveling out the exaust until you have the pedal darn near floored and then it straightens out"
I could be wrong here, but it's my experience in trouble shooting my '91 Mustang.

Good Luck and let us know how it goes!

 

Almost sounds like a bad TPS. It may or may not cause a code to be thrown. I had very similar symptoms on my Explorer at one time. Without a scanner to pull the codes, there may not be an easy way to determine what the problem is.

-Joe

 

Also had that problem (at the same time) as well. TPS voltage was over a volt and caused all kinds of problems.

 

*****problem solved*****
thanks to the help of __ SMOKEM331 ___ over at ford truck enthusiasts

i wouldve never thought of what it turned out to be in a million years as the culprit


BAD MAP SENSOR