MAF P0171, P0174 issue
Thread Starter
Teching In
Joined: Nov 2007
Posts: 30
Likes: 0
From: Arizona
MAF P0171, P0174 issue 2002 pontiac firebird, replaced what I thought was a faulty MAF sensor about a year ago. Long story short, I replaced the stock unit with a SLP MAF, and the computer is throwing codes about being too lean on bank 1 and 2 (again).
I'm almost convinced that the SLP sensor is faulty. If I clean the MAF with MAF cleaner and clear the codes the computer in the vehicle is happy for a random amount of time (a day, a week). I have been unable to find any vaccum leaks, and I have not replaced the PCV valve.
Since I don't have the original MAF what would be a cost effective replacement (other than the stealership). I really don't want to throw a few hundred dollars at this, if the fix is simpler. So I'm asking what could I have missed? The vehicle engine is very near stock. Only a catch can, a new K&N filter, and MSD wires. The car runs absolutely fine otherwise.
Suggestions on what it might be or what would be the best replacement MAF other than the SLP version?
Thanks
-JB
I'm almost convinced that the SLP sensor is faulty. If I clean the MAF with MAF cleaner and clear the codes the computer in the vehicle is happy for a random amount of time (a day, a week). I have been unable to find any vaccum leaks, and I have not replaced the PCV valve.
Since I don't have the original MAF what would be a cost effective replacement (other than the stealership). I really don't want to throw a few hundred dollars at this, if the fix is simpler. So I'm asking what could I have missed? The vehicle engine is very near stock. Only a catch can, a new K&N filter, and MSD wires. The car runs absolutely fine otherwise.
Suggestions on what it might be or what would be the best replacement MAF other than the SLP version?
Thanks
-JB
You have a vaccum leak. Replacing the MAF wont fix it. Find and fix your vaccum leak. Try spraying brake clean or choke cleaner around your intake gaskets and see if the engine stumbles at all
maf hi, it seems like the after-market mafs make the car run lean. i had a Granatelli and it would cause my car to run lean. i had already sold my stock one so i just bought a good used one. you can find them for 40.00. mine has worked fine and i have not thrown any codes. put a stocker back in.
Thread Starter
Teching In
Joined: Nov 2007
Posts: 30
Likes: 0
From: Arizona
Matt, would that be behind the throttlebody I presume? Or am I way off the mark?
Cleared the code again to day (drove fine the whole day, until 1 minute from my house) and to my surprise it also threw a P0300 (random misfire). No blinking SES, no loss of drivability, idle etc. WTF.
Thanks everyone for all the suggestions. I appreciate the help. I'm definitely going to put the stock MAF back on. I'll have to wait until Sunday for a moment go leak hunting.
Cleared the code again to day (drove fine the whole day, until 1 minute from my house) and to my surprise it also threw a P0300 (random misfire). No blinking SES, no loss of drivability, idle etc. WTF.
Thanks everyone for all the suggestions. I appreciate the help. I'm definitely going to put the stock MAF back on. I'll have to wait until Sunday for a moment go leak hunting.
Last edited by Wisp; Jun 26, 2010 at 01:53 AM. Reason: spelling, additional details.
Thread Starter
Teching In
Joined: Nov 2007
Posts: 30
Likes: 0
From: Arizona
While following Matt's advice, I found a hairline crease on the return line to the throttle body. The line was slightly kinked in a way that (I assume) made the vaccum leak intermitant. Replaced the line, checked the others (and the plug wires for that P0300) and reassembled. Hopefully, this will fix it. 
