crappy idle and diagnosis..

eclipsed at 3am · #1 08-17-2006, 11:34 PM

My cel is on, and the car idles like crap. It stutters a lot, and really struggles. Sometimes, it idles great. Right at 900(where I like it) rpms. But most of the time it will idle super lean and the rpms will bounce up and down between 200 and 1000. Today it was even stalling a couple times. When I drive, it sometimes stutters, it feels like i let off the gas a little bit and then back on. very irritating.

Anyways, point of the story. I went to advanced auto and had them scan it. The printout was maf and throttle position sensor malfunction. Ok, thats fine. So heres my question: Wouldnt it be something like the IAC? or do those two sound right? Also, I think Ive heard around forums or whatever before that sometimes when an engine component, sensor, whatever is bad, it will turn on the cel but the cel will report something else as being bad. Is that true and/or could that be the case here? I know that might sound kinda dumb, but I'm just making absolutely sure before I buy these parts.

Could the maf throw a cel if its hacked?

Blackcrow64 · #2 08-17-2006, 11:41 PM

The MAF could throw a CEL if its hacked up, but it sounds more like the IAC is going bad if ya ask me... Maybe we should talk more about this hacked up MAF first though. lol

eclipsed at 3am · #3 08-17-2006, 11:59 PM

we can talk about it all you want i guess lol... by hacked i mean the honeycombs are taken out thats all.

Why would the scanner say TPS if it might be the IAC?

Blackcrow64 · #4 08-18-2006, 05:57 AM

Oh, well if its just the honeycombs then thats not causing it. I thought you meant like the harness to it was hacked up or something... I donno about the TPS, I suppose the IPS on it could be going bad and causing problems... I didn't put a whole lot of thought into it before I said the IAC because it sounds like a typical IAC problem. But if the code was for the TPS then the IPS could very likely be the problem. Or it could be some other off the wall thing. Gotta love DSM's. lol

GTPSPEED · #5 08-18-2006, 01:50 PM

the tps is pretty cheap,you can get them from other forum members pretty easy.i think that is on the throttle body i think.just replace both

blk_srt · #6 08-18-2006, 03:53 PM

A hacked mas can cause a shitty idle. The honeycombs are there to stablize the insoming air and with out that it can get messed up readings.

eclipsed at 3am · #7 08-18-2006, 05:01 PM

alright then.. well a guy i met at the local ricer hangout is about to go 50 trim with a gm mas, so he was gonna sell me his 2g mas. I think his is hacked though, but his car idles beautifully. He also has about the same mods as me, except he has 264 cams and 550 injectors, and beefed up internals. Does the throttle position sensor really have as much to do with the idle as an IPS does? and whats the difference between an IPS and an IAC?

"""bostonjoe98gs the tps is pretty cheap,you can get them from other forum members pretty easy.i think that is on the throttle body i think.just replace both"""

bostonjoe, when you say replace both, do you mean both sensors, or the TPS and the throttle body?

Killa · #8 08-18-2006, 05:10 PM

If you need IAC ( ISC ) let me know, I have a perfect working one, paypal me, and if that IAC I send you, not working like I told you, you can get your money back.

blk_srt · #9 08-18-2006, 05:40 PM

IIRC you can compensate for a hacked mas with your tuning device. Its possible its the tps but not likely, best bet is the ISC or the FAIV

eclipsed at 3am · #10 08-18-2006, 05:41 PM

what is a FAIV and does anyone have a ISC for sale?

blk_srt · #11 08-18-2006, 05:45 PM

Killer just told you he would sell you one, and the faiv is a Fast Air Idle Valve and its a gay little thing that is notorious for causing idle surge

Blackcrow64 · #12 08-18-2006, 07:51 PM

IPS = Idle position switch... 2g's have it and its gay. lol

kjewer1 · #13 08-19-2006, 10:48 PM

Never heard of an IPS? I'm assuming you mean the part that I call the closed throttle switch, which only the 1g has. The 2g simulates it in the TPS, which is why there is a 4th pin (1g TPS has 3 pins).

blk_srt · #14 08-19-2006, 11:51 PM

I was going to say there....

Blackcrow64 · #15 08-20-2006, 12:28 AM

Quote:

Originally Posted by kjewer1

Never heard of an IPS? I'm assuming you mean the part that I call the closed throttle switch, which only the 1g has. The 2g simulates it in the TPS, which is why there is a 4th pin (1g TPS has 3 pins).

Oh, well I thought that the IPS was on 2gs too. Now that I think about it all the cars we work on do have 6 bolt swaps in em... I always refered to it as the IPS. Is this actually not the correct term?

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