help.. my car sucks

[froggyknh]

I have a 93 ATX. I have had nothing but problems since day 1. Right now, the idle is screwed up. Sometimes when in park, or in gear and stopped, the idle drops to 500 RPM or less, and ocasionally dies. I reset the idle (unhooking negative battery cable, etc) and now it doesn't die as often, but after I have been driving a few minutes, the idle goes up to 1600 RPM when i stop, and up up to 3000 RPM when iI put it in park after driving appx 10 minutes. It still idles low when I first start it too. It also gets crappy gas mileage. (14-16MPG)

I had a mechanic friend check for codes and came up with nothing. He said it sparks great, and doesn't think its a cylinder misfire. He is completly baffled. I have replaced tons of parts and I am sick of putting money into it, and nothing fixing it.

I have replaced:
valve cover gaskets and tube seals
intake gaskets
plugs (twice)
wires
EGR valve
DPFE (map sensor?)
IAC motor
Throttle position sensor
Mass air sensor
timing belt
fuel filter

If anyone has any other suggestions, that would be great. I love the car, but I am about ready to give up

 

[whiteman_01]

I would first off try resetting the idle again. Only this time you want to load the motor right after you start it.

Within 10 seconds you want, AC on max, headlights on, shifter in drive, and turn the wheel side to side.

 

[93rev2sev]

The only thing I would add to your list is o2 sensors and vacuum lines.

(pssst: vacuum lines)

 

[froggyknh]

yep, knew I'd forget something. O2 sensors have been replaced, and vacuum lines have been checked, and broken/cracked lines replaced.

 

[froggyknh]

I have also:
replaced head gaskets
cooling system flush
tranny rebuilt
new intake coupler hoses

 

[93rev2sev]

I suspect the ATX for some reason.

 

[froggyknh]

was rebuilt less than a year ago. Why would the tranny mess up the idle?

 

[Endri_SHO]

the only thing that might be fixing your problem, is vss ( vehicle speed sensor) replace that and reset the idle again.. tell us what happens.. i had the same issue in my 93 atx and after e new vss was installed the issue was gone...

good luck

endri

 

[froggyknh]

Great. I'll have to do that. I bought a new speed sensor a few months ago, because of some downshifting problems, but never put it in cuz it looks like it's going to be a pain to change (and the one on the car was not plugged in, unsure why) After we plugged it back in, it quit having the downshifting problems, so I wasn't so concerned about replacing it right away. (was gonna wait till we did the power steering rack). But we will change the speed sensor and see what happens.

 

[93rev2sev]

Dastardly ATX's

 

[froggyknh]

Well..... was driving on the interstate today.... when I got off, my car died on the ramp....seemed reluctant to start back up, but it did.... now has a horrible upper end knock, with a bit of a squeak...... pulled over immediatly and had it towed home.

Also, the past few days I noticed my oil light coming on when I stopped, but it went off as soon as I gave it some gas or started going again. Checked the oil, and it was full.

So now it sits till we figure this one out...