I recently replaced the exhaust system on my car including the Cat. When i start the car it runs normal no smoke but smells weird, and it seems once it starts too warm up it will start smoking blueish smoke. if you rev it it comes out of the deceleration. I know that my valve stem seals need to be replaced on the car would this be the problem? I was also getting code 33 and 34 for the mass airflow, could the valve stem seals cause it too give those codes? or is the mass airflow the cause of the smoking. I replaced the mass airflow a couple of years ago. thanks

 

as for parts store MAFs .I personally have been through 8 different ones. they are all re-man in CHINA!!(never buy anything that says "a1 cardone" on the box) and they are junk. I ended up buying one from my local GM dealer for.....$1100 no less.and blue smoke on decel is an indication of what you already know,time for a valve job on those heads.and no, the MAF doesent cause blue smoke.plenty of black when they die ,but no blue

 

I was looking at my MAF and thought it looked pretty cheap for the price. I'll bring her down too the mechanic and see what he says about the MAF thing, and if he could get me a good quality mass airflow. Thanks for the help!

 

A word of advice: DON'T DO THAT. Your mechanic will hose you big for a knock-off that will burn out quick.

Search eBay. You might get lucky and find a NOS or other new GM MAF for dirt cheap (I got my $280 MAF for $50, NIB).

And then you need to examine the air intake and find out why the MAF sensors keep burning out.

 

it takes a very expensive flow bench type thing to accurately test a MAF. I would suggest a NEW one .certainly not a re-man one. (made of chinesium!)

 

definately gas/air prob. valve seals normally just puff a bit of white smoke when first started due to oil settling in the head when not running..