My mechanic said 90% of the time when p0171 and p0174 come up on a 97-03 f150, it is due to vacuum leaks. I just had those codes a couple weeks ago. I just replaced a couple hoses and it's good now.

 

now ive seen somewhere you can use rubbing alcohol on the maf. now is that safe or not?

 

No it is not.

 

Check for a collapsed CCV hose on the rear of the intake / throttle body. It goes from the PCV on the passengers side valve cover to the top rear of the intake, just barely under the cowl at the firewall.

Mine was showing the same codes and I first cleaned the MAF, only to later discover it was a collapsed hose. Amazon sells that hose (OEM Spec - Ford part) for about $25.

 

When I first got my truck and was trying to solve my surging idle I read to use rubing alcohol with a q tip. That was almost 2 years ago with no ill effects. Of course I would use the proper cleaner today. My surging idle was lower intake gaskets. Lean both Banks

 

I'm geting a PO174 code from my "99 F150 4.2L pickup. That's too lean on the right back (passenger) cylinders. Both of the little wires, filaments the Mass air sensor are about twice as thick as the filaments, about 1/4" long, and are a light grey color. I use a K&N filter, which is pretty dirty at the moment. Is the sensing portion of the filament supposed to be this color?

Thanks, Shoman