Ok, here's the deal.
I have had a problem with the idle for a few months now. Once the car is warmed up so that the idle is supposed to be about 550 (in drive, no a/c), the rpms will start dropping to ~400 rpms, then it will jump up to ~650, somedays are worse than others. Also, the exhuast has a strange popping noise while this is going on. with the a/c on, the problem practically goes away, although it might be due to a higher idle speed. engaging the fan with my fan switch initially makes it stumble, but after a few seconds it is just like w/o it on at all.
I have replaced the dist. cap and rotor, removed and cleaned the spark plugs, experimented with different spark timing, lowered fuel pressure back to stock, ran without an air cleaner, changed a few spark plug wires, installed an MSD coil, and checked for vaccum leaks.

The only thing that seemed to help was cleaning the spark plugs, now the problem still exists albeit not as severe. I'm at my wit's end here, soon I will have to break down and (gasp) take her to a shop.

Thanks,
Brandon



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White '92 Firebird w/ 305 TBI. Open element w/ non drop base, increased fuel pressure, TBI spacer, Hedman Hedders & y-pipe, no cat, cat-back exhaust

 

Well, the popping noise is usually a misfire. Do you have the right plugs? Are they gapped right? Also, stupid question but i did it, are all the plug wires connected and in the right place? If you put one wire on the distributor wrong the car will have a nasty misfire and horrible idle. i know because i did it once. Check those things out and get back to me.

 

I had my wires mixed up when I cleaned the spark plugs, and it ran like SH*T. As for plug gap, I'm not sure, i have the +4s on there and I don't think they can be gapped. I have a hypothesis for the problem, though: I did the field service mode to see if the car is in open or closed loop, and i found out when it starts stumbling that sometimes it will knock back into open loop. Wouldn't this be caused by the o2 sensor not being hot enough?

 

BTT

 

I am not sure what would do this. Is your TPS adjusted right? did you somehow move the distributor and change the timing? Other than that i am not sure. BTW, kinda feels dumb when you put the wires back wrong doesn't. Dont worry, i did it too. I felt like a dumbass. That is why when i work on my car i take my time and dont rush anything.

 

btt again

 

Your car just sucks!
J\k
oh just thought of the sparkplugs. I wounder it is the +4's.

[This message has been edited by Zar (edited September 13, 2000).]