Car was idling for about 15 minutes and never went into closed loop. Had it revved up to 2k for a few minutes and the temp was up to 220.

o2 voltage varied from mV 408-480, also switched back and forth between lean and rich.

maf 5
proper step lean
base PW (ms) 1.6
loop open
o2 crosscounts 16 to 33
iac 20
A/F learned - no
integrate 128

temp reads fine, so I guess the sensor is good. I don't know if the maf is reading right or if the o2 is varying enough.

Can anyone make any sense of all that?

no codes yet (had the battery disconnected before driving 15 mins out to my friends house where the scanner is.

 

im having a similar problem,
my car seems like it doesnt want to go into closed loop.

my primary suspect is my recent valve adjustment,
I heard overtighting a tinsy bit of valve will possibly cause
stuck open valve at warm temperature(due to metal expading)
and ECM tries to send more fuel in to compensate for its losing compression.

so yeah if uve adjusted valve recently keep that in ur possibility list

 

I am having the same exact problem and my car stalls when i come to a stop

 

The MAF reads 5? As in, 5 volts? Because (if my dusty brain remembers correctly), that's just the reference voltage. When the MAF works, it varies that 5 volts back to the computer.

Could be a bad MAF; they've been known to go bad and not throw a code. Have you done a physical inspection yet? The orange frequency film inside should be perfectly FLAT, no wrinkles/bends/creases etc. And my mechanic told me once that he saw a MAF that threw no code, but the circuit board inside was melted!

sogabe, I'd think your car would still go into closed loop, but you'd probably get a "rich" code from the computer.

DaSkinnyGuy, does it happen only after you've reached "highway speed" and come to a stop? If you stay under 40 mph, does the car stall at all? I'm thinking a stuck EGR (won't close all the way, causing a stall) OR, if its an automatic, the TCC solenoid could be sticking (engages TCC and won't release when you hit the brakes).

 

This happens when the engine is fully warm and either i am decceling down a hill or when i am coming to a stop at a red light