Okay, I've had my '90 FC for quite some time now and it has always given me a little bit of greif when it comes to how it "idles". It usually idles rather smoothly at anywhere between 1100-1400rpms until it is at operating temperature. Once it reaches operating temperature, though, it drops off to about 400rpms and idles rough for a second and acts like its about to shut off (i.e. 400rpms, 50rpms, 400rpms, 50rpms, ect.) and after a bit it WILL shut off. I've changed spark plugs, spark plug wires, and an 02 sensor without any luck. My last idea is to change ALL of the vacume lines (possible vacume leak). If ANYONE has an idea of what could be wrong with my car and could give me a little advice, I would really appreciate it. THANKS!!!
-Lucas

 

Still have the Accelerated Warmup system in?

 

when i first got my TII we had that issue - it turned out to be a HUGE vac leak, once we located it and fixed it, it has a rock solid 700rpm idle.

 

have you tried cleaning out your full injectors?

 

Hmmm, thats what I thought. Mine has the original vac lines (which are very brittle) and I've changed out 2 or 3.

Oh, on an off topic note, what was the original redline for a 90 GXL 5spd? I think that mine may have originally been an automatic because it redlines at 7000 and I've seen pics (not sure if they were N/A's or not) of tachs with 8000 rpm redline.

 

I put some STP Fuel Injector Cleaner in about 1400 miles ago, didn't really help.

 

I would change all your vac lines and gaskets (if you haven't already). Check your TPS.

Send your injectors to CruizinPerformance ( http://www.cruzinperformance.com/fuelinj.html ).

 

3 spoke rims... ahh old school rotor style, nice.

 

Thanks. They are a little old school with a little new school (CF Inserts on the lug cover plates.)

 

Not to sound like a noob, but what is TPS?

EDIT: Throttle Position Sensor, n/m.

 

Change all the vacuum lines, clean the BAC valve, adjust your TPS. Don't waste time with things like injector cleaner...

9x out of 10, idle problems are vacuum leaks. The other, it's a maladjusted TPS or a bad/sticky BAC valve.

 

mines 8 grand
I just ran outside and looked

 

7k was just on the autos and I believe the verts as well.

 

Us S4 guys are only allowed 7k until the buzzer, 7.5 and the fuel gets cutoff. Maybe he has an S4 guage cluster? :shrug:

 

S4 N/A 7000
S4 TII 7000
S4 A/T 7000

S5 N/A 8000
S5 TII 7000
S5 A/T 7000

 

I think my car was probably origanally an automatic.
1. My tach redlines at 7000rpms
2. The "PRND...HOLD" thingie is on the guage panel
3. I have what look to be plugged trans cooler lines on my radiator
4. When I took my shifter apart I saw an unplugged plug
No big deal, I guess, considering that it is at this instant a 5spd, not to mention I'll be spared swapping the tach when I do my TII swap (hehe). I also think that my final drive is probably 3.90 if it was an auto.