2G low low idle for a few mins then goes to normal idle

[tode5tool]

ive searched for this but i cant find any as specific as my problem is, im posting in newbie cuse frankly im a dsm noob, but not a noob mechanic, just a bad speller.. so ive got a stange problem with the idel, before i go on ive checked the BISS and it does works, when i start up wether or not its hot or cold the idel is around 400 and gets as low as 200 but dont die, then after about 5-15 mins of running, driving or ideling for the duration it all of the sudden goes to a normal idel, around 900-1200. it also sputers, rough idel before it gets normal. once it gets normal i can turn it off then turn it right back on and it does it all over again. it seems to me like the computer catches the idel problem then fixes its self, then it forgets after its been turned off. what would cause this. i dont understand it. its not to bad i can deal with it for the time being but is very annoying.

ive checked the wiring and it all seems in fair condition, evrything is hooked up, tho a week or so ago my freind brought it to the mechanics after we bought it and he found that the egr wiring was disconected. could the egr be messed up cuse of this?

on a second note, before the car "fixes" its self.. it has a really really rich air/fuel mix before the turbo, and only gets beter becuse of the boost making the air fuel mix more stoch. any ideas??

 

[ttetzner]

try the IAC sensor, its a cheap fix and can really mess with the idle in different ways, when mine went it would idle rough, surge, idle low and run fine at times

 

[tode5tool]

ok so i tested the ohms on the iac and it running around 5-6 ohms and i know it should be like 28-33 right. i found it kinda odd that all of the nodes tested so low .. allmost the exsact same.

 

[KevinRR]

The measurement should be 28-33 Ohms and should be tested when it cool. You can get a new ISC from DSMISC Automotive (New ISC Supplier)

 

[tode5tool]

well i went to a junk yard and found a IAC from a 92 talon, tested it and its ohms are exsactley the same as the one on my car now 1k test 5, 10k test 11. i dont know if im not using the multimeter right or what. but i put it on the car and it does the exsact same thing. high idle for a few mins then it progressivly gets lower and lower till its around 500-600 and sputters and junk. then after a few mins it goes to a normal idle. theres also a hose that comes from the thottle body to a little sensor or somthing then splits off to 2, one goes to a bug jug like thing under the battery then another has been cut and i cant find where it goes.

o.. and another thing. i disconected the IAC and ran the car, idle was realy high but i decided to hook it back up.. im realy not sure thats the problem. tho im going to keap trying the IAC.

 

[tode5tool]

i was doing and oil and air filter change yesterday, and my MAS was allmost falling off the intake pipe. i found some bolts and got it hooked back up, but it seems like its runing beter, a higher idle i mean even at its worst. could my MAS be messed up? or could a MAS make idle do what its doing??

 

[belize1334]

A poorly connected MAS could cause the car to run very lean as it's pulling in unmetered air from the leak. That still doesn't quite explain why it suddenly fixes it but you should definitely fix the MAS issue and it should help. Your ISC is definitely showing symptoms of needing replaced so go ahead and do that.

Have you tried pulling the engine error codes. There are some codes that the engine will record which won't cause a CEL but could be useful for diagnostics.

 

[tode5tool]

ya i was lookin at the mas connector and the clip was broke on it and was loose, so i zip tied it up and is secure now, but i know the maf is bad cuse i can tap on it and the engine responds. also i still need to find a good iac, junk yards dont have many options.. plus the iac i got from that talon does the same thing.. make me wonder if its just the mas and not the iac at all.

it dont throw an engine light and the last time i ran a diagnostic on it it had no codes.

also it dont run lean, thank god, but it does run very rich.