is it possible for the mass air sensor to go partly bad. what i mean by that is- can it be fualty and not throw a code. the reason i ask is i just got the z out since its winter break and it runs like a pig, it idles like it got a huge cam, then when i give it a little gas in park up to maybee 1500 rpms it has a noticeable shake or miss-can also see the engine shaking a little. but above 2000 rpms it seems to go away, but its still running rich, put your head near the tail pipes and your eyes start burning.

 

Yes MAF's can go bad and not set codes. I replaced mine last year after trying to tune the air fuel over and over again. It kept changing. Put on a new MAF and its never been better. You could try cleaning it first, sometimes dirt gets stuck on the fine wires in the sensor. Be very carefull not to break them though.

Your problem sounds more like a misfire could be bad wires, moisture build up in the opti. Did you use fuel stabilizer when you parked it could just be stale gas. You could unplug the MAF and see if it runs better also.

 

i hope its not plug wires i just put taylor cut to fits on about a year and a half ago. i was also thinking about moisture in the opti(man i hate that thing). and as far as the gas goes it was pretty low, about to run out, so i got 10 gallons and put in it.

the reason i thought it was the maf is because i have the pcv valve out the pass. side vavle cover plumbed into the intake side of my blower, so didnt pull it apart yet but i would think it would pull some oil vapors and send them through the maf possibly killing it???

 

got an update. unplugged the maf and the car didnt start. so plugged it back in and had to give it 1/4 throttle to get it started. now i have two different scanners, one is the scanmaster the other is an actron. in the scanmaster everything looks fine, but when i put the actron on in open loop(when it doesnt wanna idle) the iac possition is 160 and the injector pulsewidth for both banks are 4 and somtimes switch to 9. now in closed loop it actually idles good, but the short term fuel trim one one side is different than the other, the iac is about 85ish,and also in closed loop the inj pulsewidth bounces from 4 to 9 then to zero and then hte car dies. what the h$!! is going on here

 

Don't know how much this will help but it is recent experience. Just put my motor back together about a month ago after I replaced a valve. Car was running ok but according to the scantron one bank was running much richer than the other (110 vs. 120). I unplugged my MAF and low and behold the scantron was reporting everything was working wonderfully (125-133 block learns for both banks). I am awaiting my new MAF. I think I may have messed the old one up cleaning it. We will see.

 

What year is your car? Makes a difference in the answer, because the OBD-II PCM's have increased capabilities for comparing the MAF's figures to expected values derived by looking at things like RPM, throttle position and engine load - in other words, a rationality check. OBD-I can't do that.

Why not add a "signature" with basic info about your car, like model, year, trans, any mods, etc. That way people can provide you with more accurate information.