Help me fix this gremlin

[Dodobrown]

Currently and for the past few weeks i have been running a 1221 code or faulty 02 sensor code. For the life of me i cannot seem to find what is causing this issue. Symptoms include rough running in rain (maybe related). Slight surge at idle, random misfire.

items replaced

02 sensor (bosh and untested)
Tps (made things better also tested and calibrated)
new plugs, wires, cap, rotor (bosh)
new air filter
cleaned icv (untested)
valve adjustment

the only thing this leads me to believe is i have a phantom vacuum leak some where in the line up or a fuel delivery issue.(i dont believe this would give me a cel tho) Perhaps i have a faulty 02 sensor.

Any one got any ideas where to look next. Im considering testing all my injectors to see where there at and possibly soaking the engine in carb cleaner to hopefully find the the vacuum leak assuming there is one.

[jlevie]

I suspect intake leaks. Have a shop run a smoke test on the intake & block.

[Dodobrown]

i herd about this "smoke test" is this something i can do my self? can i just light a big cigar and blow smoke on my engine?

[billybobjoseph]

Did you reset the brain after you replaced the O2 sensor?

[billybobjoseph]

Here's a thread on homeade smoke machine. http://www.rx7club.com/showthread.php?t=514037

[Dodobrown]

yes i did reset. i get about 10 miles before the cel comes back on. the only gasket that i havent replaced is the intake manifold which i'll be doing any way when i paint it, which might happen sooner then later

[Dodobrown]

There is something very odd about my problem. it will work one day 100% all day long and then the next be riddled with misfires. the only way i have been able to accurately recreate this is when its raining which on occasion will eventually clear up. would this mean i have a electronic issue?

[MTechnikII]

It seems to me thats a Air flow meter problem, just try another AFM and see if you see any changes, also try to clean the O2 sensor plug and trace the wire to O2 sensor to be in good condition, sometimes ( Has hapened to me) I see wires that look OK but the actual copper inside is brocken but the insulation looks in takt,
not sure about this one but , there is a relay for O2 sensor, see if you can try another one, it's for the O2 sensor heater,
I had a mechanik smoke testing my cars engine, I didn't know where the leack was but the smoke test showed its from one of the injectors O rings, before I replaced it I did try this
get a plastic tube about 3 to 4 feet long mayve about 1/8" thick something like a vaccum tube on the fuel pressure tube, put one end on your ear and try to probe different areas with the otyher end, with the engine running , if there is a vaccume you can clearly hear the hissssing noise.
hope this helped
Henry

[Dodobrown]

thanks dude that was actually quite helpful im gonna give all that a try tomorrow as long as its not raining