Hi, my car is giving me code 33, and I fallowed GM service manual to diagnose this code, and it told me to replace the maf sensor. I checked with my scan tool and it showed me the ecm was reading 17 gm/sec @ 950 rpm , at the same time my rpm gauge was showing ~1500 rpm. When I searched on TGO, I found out that I suppose to have 7~8 gm/sec at idle. Then, i scanned my 97 350 maf Vortec truck to compare it to the Camaro, and the truck was reading about 17 gm/sec at idle also. Now I am confused is my maf bad or what? I do not want to spent $200 on maf sensor and it may not solve the problem.. car's background: 85 TPI 406 ci, Super Ram. cam Dur 224 224 @.050 Dur Adv LSA 114. ECM is converted to 165 from 870. Maf is stock from 85 . E6 broadcast and the only thing modified in the chip is the fuel injectors constant to compensate 30lbs injectors. Also the car been sitting for a year. Thanks in advance

let me ask this, how much gm/sec should i get if the maf is disconnected and ignition on / engine off?

anybody? is it a hard question or what??

Without actually check I would image you should get 0 gm/sec or close to that with the car not running.

When you had the scan tool hooked up and got 17 gm/sec @ 950 was this at idle or at 1500 rpm. Your original post is confusing, you were getting two different rpm readings so which one was correct?

it was 17 gm/sec@ 950rpm

I once had a code 33 on my Iroc. I replaced the MAF but I didn't see much of a difference so I had my timing adjusted using the distributor which helped me out a lil. I don't know exactly what the timing is supposed to read, I just adjusted it until it ran better, lol. Also, check your spark plugs and wires to make sure they are all good because that could cause a code 33, I think. Since you've had the code 33, has the car done anything abnormal, like surging or running rich?

well my timing is set at 10 deg, and i think that's what it supposed to be at. my car was surging, and running very rich. I also replaced my plugs.

I believe the timing is supposed to be set at 6* from the factory.

I'll adjust it to 6 deg, but I do not think it will make a difference for code 33

You're right it won't.

I got it, my burn off and maf power harnesses were connected to the wrong relays. Here is a flow chart for code 33 just in case if anybody needs it