Bear with me, this will be a long post so that I can be as descriptive as possible.

I've had an intermittent problem with my 88 IROC 5.7 TPI since I bought it last November.

Symptoms:
1) Won't idle but will run. If I back out of the throttle and hit the brakes, the only way to keep it running is to put it in neutral, left foot brake and use my right foot to blip the throttle. Normally, the car idles at around 700rpm. When it's acting up, it'll drop well below 500, by itself it will raise to about 900 then drop back up 500 and hunt. Sometimes it stall (always if I hit the brakes) sometimes it doesn't.

2) Won't start hot. In these more rare occasions, if I continue to crank, I can eventually smell fuel so I know that I am getting fuel.

3) When sitting at idle when it acts up as described in #1 above, sometimes if I just shut the car off and start it back up. Everything is fine.

When:
1) After the engine has been through multiple heat cycles to 220 and back. It does not happen all the time, but enough that every time I drive it, I anticipate it happening.
2) Full tank of fuel or lower doesn't seem to matter. I don;t think that this is a fuel delivery problem since I smell fuel when it stalls and doesn't want to start.

What is going on?

I have done the following already (not necessarily for this):
1) Cleaned out fuel system (BG MI300)
2) Changed the O2 sensor
3) Had these symptoms occur with the ECM hot and cold (by using the heater and rolling the windows up/down). Someone on this message board mentioned that the ECM can get wacky if it gets hot
4) New battery
5) Completely new cooling system and hoses

Any ideas would be greatly appreciated.

 

I would start to look for vacuum leaks! Power brakes get their "Power" from the vacuum created inside your engine. Check your vacuum resevior (the big ball hidden inside the drivers side front fender) sometimes they crack, check for split or broken vacuum lines and finally do the carb cleaner check all around your intake base, runners and TB. Do you throw any codes? Did you do anything to your car just before this started happening? It sure sounds like a vacuum problem to me, and that would be the first thing that I would suspect, provided you're not tripping ECM codes.

 

Please be gentle - I should know this.

Where do I access the diagnostic connector to jumper A and B to get the codes? I have the Haynes manual and it shows this nice, obvious, easy-to-access location that looks nothing like my IROC.

I have already laid on my back on the passenger's side floor and found a vertically-mounted black box which I assume is the computer. Unfortunately, lying on my back, the absolute smallest face of the box faces downward.

OK, let me have it...

 

Check in the area around the fuse panel, that's where it is on my wife's '91 bird.

------------------
DR Stevens
1984 Trans Am 305HO L69
sucks gas, hauls ***
1991 Firebird 305 LO3
for days when I need a/c

 

I am having the same exact symptoms as you, Keith. My car is a 86 305 TPI. I threw a code 32..there are 3 possibilites for code 32, the vacumn lines, barometric pressure sensor circut, and the EGR. I was told to do the EGR and check the vacumn lines also. But most everyone i talked to when describing these exact symptoms you have written, has said EGR. I am not saying to forget the vacumn lines...by all means check that too...but the EGR valve may be a possibility as well. Hope this helps.

------------------
1986 WS6-Equipped 5.0 TPI Trans Am
Random Tech High-Flow Cat
Two Chamber Flowmaster Muffler
Megs Custom 4.5" Stainless Steel Rolled Tips
1999 Grand Am GT In-Dash CD Player w/Equalizer(fits like '86 original)
5% Tint On Rear, 35% On Sides
http://www.pitt.edu/~zyhst/trans86/

OTHER RIDE:
1998 C5 6Spd. Corvette Coupe
Silver w/Gray Leather Int.
12/14 Options
Stock(for now)
Best 1/4th: 13.5 @ 104.4MPH

 

I'll try to check the codes then look into the EGR, barometric pressure sensor circuit then start digging around the vacuum lines.

Hey PhantomTPI. I see you're hosted at the Pitt web site. I'm a Pitt grad (CAS '87). Nice to see another Panther lurking about.

Thanks guys.

 

Keith...

Sorry to misguide and dissapoint you, but i dont go to Pitt. My bud does, whom I've known since kindergarten. The only reason i am hosted there is because that is a temporary page for me. I am building one myself that will include picutres of me, descriptions, more pictures of the TA and the Vette, and links to my freind's pages(all of whom own F-body's). I am writing the HTML code myself, and since I just started taking that this past semester, its taking a while But I will have my new page up soon...hosted on a different server(that page will get deleted). Sorry for the confusion.

Anyway, yes, definetly check the vacumn lines...but if you dont find a problem there, the EGR, Baro sensor circut could be other causes...dont leave those out as possible causes. As soon as you find out what is wrong, post here....because i am having the same exact symptoms as you, and would like to have this car running at its optimum. Thanks

------------------
1986 WS6-Equipped 5.0 TPI Trans Am
Random Tech High-Flow Cat
Two Chamber Flowmaster Muffler
Megs Custom 4.5" Stainless Steel Rolled Tips
1999 Grand Am GT In-Dash CD Player w/Equalizer(fits like '86 original)
5% Tint On Rear, 35% On Sides
http://www.pitt.edu/~zyhst/trans86/

OTHER RIDE:
1998 C5 6Spd. Corvette Coupe
Silver w/Gray Leather Int.
12/14 Options
Stock(for now)
Best 1/4th: 13.5 @ 104.4MPH

[This message has been edited by PhantomTPI (edited May 12, 2001).]

 

If you dont pull any codes that indicate anything obvious something else to check would be your IAC valve. I had almost identical symptoms as you and couldn't figure it out untill I got a scanner. It would screw up when the engine got hot and stick.