Changed out my gauge cluster last week and now my idle surges and sometimes stalls out.
Probably a coincidence with the gauge swap, but I couldn't find anything really related to my problem when I searched.
Car runs great when driving, no stumbling or anything, WOT feels good as wel, but it will sometimes stall when I slow down and press the clutch in, happened twice today, once when I was turning into a parking lot.
Car isn't throwing any codes.
I'm going to clean the IAC tomorrow and check for any vacuum leaks, but any input from you guys is appreciated.

Here's more info on the car,
88 Formula, T5, Holley StealthRam, stock 305 motor, no EGR (also deleted from the prom), stock manifolds, A/C Delete, K&N Air Filter.

 

Yeah sometimes stuff can go bad out of nowhere. When it happened to me (similar idle problems w/ no codes) it worked great, I changed my oil, then it didnt work great anymore. Kinda drove me nuts, kept wondering if it had something to do with changing oil LOL! Its probably not related to the guage swap you did. For me it ended up being bad TPS and IAC, replaced em both. I say pull em, clean em, and reset the specs (IAC 28mm from pintle tip to flange, TPS .54v, then reset the ECM).

 

Ok, I'll give that a shot as well.

 

Same here! My car never threw a code the 5 years I've had it. I warm it up, runs fine. Change the oil, start it 15 minutes later. Terrible idle, rich as heck, and an SES. I also though "WTF did I do changing the oil". Turned out to be a MAF relay

 

man stuff like that always happens. change your air filter and then start the car ease off the clutch and the rear end goes up in a big boom... lol ok so that hasn't happened to me but life is like that sometimes.
I would prolly trouble shoot things outside of your dash. for one thing check your o2 sensor. one of the only things I know of that gets used in closed loop vs not being used in open loop.
and don't give that whole well it's new so it shouldn't be causing problems. new doesn't mean it can't break

 

Well, I think it's a vacuum leak at the small nipple at the bottom of the TB. It does idle strange right at startup, not just closed loop.