after replacing parts, still missing/bogging/low idle
04-19-2008, 02:48 PM
#1
Registered User
Thread Starter
Join Date: Feb 2004
Location: Reidsville, NC
Posts: 1,736
after replacing parts, still missing/bogging/low idle
well i was having a problem after the car warmed up/fans turned on, i would lose idle; down to around 3-400rpm and the car sounding like it was gonna die and after you gas it a bit it would spit, sputter, and sound like it was boggin and then clear up around 1500-2000rpm...at that time it was throwing a knock sensor code, opti resolution code and an air code...so the car had around 138K on it so i decided to replace a few things...deleted the a.i.r. out and kept a good fuse, replaced the opti, water pump, knock sensor, msd wires, fuel filter and cleaned the MAF with the crc maf cleaner...the plugs and both o2 sensors were replaced about 250 miles prior to all of this....got everything back together and seems to be doing the exact same thing...car runs decent till it warms up and then back to ****...the car is pretty much stock with the "chokemaster" catback and a mac ypipe (!cat)...my next step was to replace the coil and control module but wanted to get some input first...tried searching a few ol threads in the graveyard and didnt come with anything...thanks in advance
for the record the car is:
1994 z28/a4
flowmaster catback
mac ypipe with no cat
for the record the car is:
1994 z28/a4
flowmaster catback
mac ypipe with no cat
04-20-2008, 09:45 AM
#3
Registered User
Thread Starter
Join Date: Feb 2004
Location: Reidsville, NC
Posts: 1,736
any other suggestions....im gonna replace the icm/coil and do the spacer mod but wondering if thats gonna fix the problem or not...i know others have had this problem but cant find the solution anywhere??
04-28-2008, 09:00 PM
#6
Registered User
Thread Starter
Join Date: Feb 2004
Location: Reidsville, NC
Posts: 1,736
havent replaced the icm yet...over the weekend i tried to see if any codes where being thrown by the "paper clip" method and strangly no codes but with the paper clip in the port, everytime i turned the key the fans would come on, this is with the car off...then i cranked it and ran better than it ever has for 10 mins or so then bogged itself back down...i swear this thing is possesed...
04-28-2008, 10:01 PM
#7
Registered User
Join Date: Feb 2008
Location: Dayton, Ohio
Posts: 100
Well, I can't really think of anything off the top of my head that would do that other than the icm. That's where I'd start. they're really easy to replace, just make sure to clean the mounting surface and use the grease that comes with it to grease the bottom of the new icm. I just put a new one in my ss. they're about 70 bucks at advance auto parts
04-29-2008, 05:29 AM
#8
Registered User
Thread Starter
Join Date: Feb 2004
Location: Reidsville, NC
Posts: 1,736
yeh replacing it isnt a problem...i believe i can get an ac delco one for around $40 but im getting tired of putting money in the car, especially just a daily driver!! i wish i could find out what it was, fix it and be done with it...
04-29-2008, 01:25 PM
#9
Registered User
Join Date: Feb 2008
Location: Dayton, Ohio
Posts: 100
yeah, unfortunately the little tester machine at advance can test just about any icm but the one on the lt1's. I'm not sure if you could test the resistance between some of the terminals. And how the car isn't dying until it's warmed up can also point to the icm. I would go to a dealer ship and I'm sure that the ICM. those are the first ones that I would start out with.
04-29-2008, 07:03 PM
#11
Registered User
Join Date: Feb 2008
Location: Dayton, Ohio
Posts: 100
oh, wow. I don't know how my last post got soo messed up but what I was trying to say in the end there was to try going to a dealership in the service center and get the resistance specs on the MAF, IAT, TPS, and ICM and try testing the resistance on them to see if they are any good. and does the car just die on its own after a bit? How does giving it throttle affect it? If you do go ahead and replace the icm I would do the cooling mod to it. Go to shbox.com you'll find how to do that on there. and I would get some emry cloth and clean up the ground wires that are bolted to th icm so you get a good connection. And like I said earlier make sure to clean the mounting surface for the icm after you remove the old one and use the grease that comes with it to grease the bottom of the new icm.
Last edited by 97sscamaross; 04-29-2008 at 07:31 PM. Reason: more info
04-29-2008, 07:27 PM
#12
Registered User
Thread Starter
Join Date: Feb 2004
Location: Reidsville, NC
Posts: 1,736
i just cleaned the MAF, IAT, IAC, TPS are all brand new...it doesnt really die just goes to around 300-500 and sounds like its barely running...when you give it throttle from 500-2000rpms all kinds of shaking, popping, and almost bogs the car if you hit it real hard...also on occasions when you give it throttle quickly it will have a loud, backfiring sound in the air intake near the ds fender...
04-29-2008, 07:34 PM
#13
Registered User
Join Date: Feb 2008
Location: Dayton, Ohio
Posts: 100
I added some more info on my last post if you haven't read it yet. so, you said that the car ran fine for 10 minutes or so and then it acts up? when and if it runs fine how does giving it throttle affect it then?
04-29-2008, 08:27 PM
#15
Registered User
Join Date: Feb 2008
Location: Dayton, Ohio
Posts: 100
when you replaced the tps did you make sure to get the prong on the throttle body into the slot on the tps?you have to open the throttle a bit and line it up as you put it on
Last edited by 97sscamaross; 04-29-2008 at 08:29 PM.