Running rough/rich/low idle?

[Pocket Chant]

So, I've been hunting down and eliminating problems with my M20 for a while now. Recently, When cold my car would sputter and try to stall out, a new o2 sensor took care of that. Driving around is great, the engine is incredibly smooth and it has (as far as I can tell) 100% power.

However, when I'm sitting at a light, it idles at 500-600 RPM and the check engine light comes on. As soon as I drive away, the light goes off. I've checked for vacuum leaks, but I'm sure there aren't any. Checking the codes gives me a rich/lean condition (1222). I'm running M50 injectors with a Miller MAF/chip, though it's for the #19 Mustang injectors, which is what Miller said was the correct tune. Not sure what's going on, could it be another vacuum leak, or maybe a leaky injector?

[bimm3r82]

check and clean ICV.. also fuel pressure regulator might be having issues...

[Pocket Chant]

ICV works, I was wondering about the FPR before, might grab a new one

[jlevie]

That code (1222) is a lambda fault. Which is caused by bad O2 sensor or intake leaks. Since you've changed the sensor, the most likely cause is intake leaks. A smoke test will find them (and is the only way of being certain).

[Kozworth]

I had this. I read up alot on it. Basically, its a vacuum leak said and done. The car runs lean from the leak at idle, but once you go the cel goes off. A lot of people have reported leaks at intake mani's, Good time to grab some carb cleaner.

[Pocket Chant]

I checked around, and it seems that the brake booster hose is cracked. Anyone know what I need/autozone equivalent?

[Kozworth]

If I remember, the vacuum hose has a check valve, and its also very stubborn to remove. Usually, the check valve will break before the hose comes off. Ask me how I know, I broke two of them.

Gutenparts should have them online.

[Pocket Chant]

So I can just use standard vacuum hose? Also, I remember seeing it somewhere, but can't find it, someone wrote up on swapping to the late model booster system. Anyone have a link?

[Pocket Chant]

Majorly stumped, and kind of pissed.

So I looked around, and found a hole in the line for the evap canister. I pulled it off, put a breather filter on the end of it, then plugged the nipple on the TB. The Check engine light stayed on until I pulled the battery.

Pulled it, started it back up and ran it, seemed fine for a bit, then it just went largely back to how it was before, only now the idle is wandering. Sometimes it stays at 600, sometimes it stays at 1000, sometimes it wanders between 1100 and 1500. Check engine light comes and goes intermittently. Sometimes it'll be on at idle, sometimes it won't. Sometimes it'll go off once I hit the gas, sometimes when I let off the gas, or sometimes while I'm at partial throttle/


I'm taking it to a shop tomorrow, but, help?

[jlevie]

Take the car to a shop and have a smoke test run. There are lots of places to have intake leaks.

[Pocket Chant]

Turns out the intake manifold gasket had broken slightly. My thermostat happened to break at the same time, and I'm also getting my condor Offset CABs installed. I'm excited to be without these little problems.


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[Pocket Chant]

So everything is ALMOST great. Leak was fixed, car drives pretty well, except for one part.

There seems to be a small bit of lag from 600-1500ish that wasn't there before. It just accelerates slower than it used to, but goes back to normal after that. Also, when I push the clutch in, or otherwise drop to idle, it dips like it's about to stall. I've read this may be a bad ICV, though mine seems to work.