MAF problems
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Joined: May 2009
Posts: 27,519
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From: Yorkshire, England
Leaning on the MAF may disturb a poor (air/vacuum) seal and may then lead to P0171/P0174.
Simply leaning on the MAF can't really cause such codes quickly as they are 2-trip codes, i.e. will NOT flag unless they occur on 2 separate drives and very similar conditions.
If leaning on it upset the MAF in a big way you'd expect P0101, P0102, P0103, P0105 (maybe some others too?).
I suppose if it upset the MAF in a consistent way (hard to see how) it could lead after a couple or more drives to such codes.
As ever, if you watch fuel trims, rev, and high trims drop then the MAF does not look a suspect.
Simply leaning on the MAF can't really cause such codes quickly as they are 2-trip codes, i.e. will NOT flag unless they occur on 2 separate drives and very similar conditions.
If leaning on it upset the MAF in a big way you'd expect P0101, P0102, P0103, P0105 (maybe some others too?).
I suppose if it upset the MAF in a consistent way (hard to see how) it could lead after a couple or more drives to such codes.
As ever, if you watch fuel trims, rev, and high trims drop then the MAF does not look a suspect.
Last edited by JagV8; Feb 5, 2018 at 03:01 AM.
Donna,
Have you tried applying pressure to the MAF while it is disconnected? (the car will run with it disconnected, but you'll get a code, I forget which...but have experienced a time or two after having the air box out for maintenance and forgetting to plug it back in) Anyway, I'd suggest tying the connector off where it is stable, start the car, then do your MAF presses. If that doesn't result in a stall, fiddle with the connector a bit.
Have you tried applying pressure to the MAF while it is disconnected? (the car will run with it disconnected, but you'll get a code, I forget which...but have experienced a time or two after having the air box out for maintenance and forgetting to plug it back in) Anyway, I'd suggest tying the connector off where it is stable, start the car, then do your MAF presses. If that doesn't result in a stall, fiddle with the connector a bit.
Senior Member
Joined: Nov 2014
Posts: 293
Likes: 35
From: murrieta, calif
Hmmm strange to see MAF's to behave in this manor. Cant say I've seen this before.
So to make a long story short - you get check engine light, P0171 & P0174 codes logged. Since you were applying pressure of some sort to the top of the MAF, led you to believe it was at fault, being that you replaced, and fault went away.
Now it's returned..... As for electrical issues, I have seen issues with the engine harness in the past on V6 and V8, early and late model. These 2 codes being logged could be a multitude of things causing it.
May need to take it to a dealer or someone who has SDD and see if any flight data has been logged along with those 2 codes. If you can get this info it will definitely help.
As for jakesdad - the slightest vacuum leak can wreak havoc. Even if you've had the intake off for injectors, did you replace the gaskets or reuse old ones? There are several vacuum hoses on the V6, some are covered in wire conduit, so you may need to disassemble to fully inspect to eliminate as cause. The upper and lower intake gaskets, these can be cut while refitting intake, doesn't take much. IMT valve O-rings fail just like the X-Type ones did, another place to look.
As I mentioned to Donna, you may need to take to dealer or someone with SDD, or has a proper scanner than can monitor sensor data, or even read flight data, this will give insight as to what the car was doing when the fault occurred. I would suggest this before throwing parts at the issue, it can..... no it " will " be expensive, and time consuming.
Keep in mind, if you've been looking at one problem for so long, you start to get frustrated. May need to go back to square 1 and start over, you " may " have missed something. I've done this when I've been stumped, just a suggestion.
So to make a long story short - you get check engine light, P0171 & P0174 codes logged. Since you were applying pressure of some sort to the top of the MAF, led you to believe it was at fault, being that you replaced, and fault went away.
Now it's returned..... As for electrical issues, I have seen issues with the engine harness in the past on V6 and V8, early and late model. These 2 codes being logged could be a multitude of things causing it.
May need to take it to a dealer or someone who has SDD and see if any flight data has been logged along with those 2 codes. If you can get this info it will definitely help.
As for jakesdad - the slightest vacuum leak can wreak havoc. Even if you've had the intake off for injectors, did you replace the gaskets or reuse old ones? There are several vacuum hoses on the V6, some are covered in wire conduit, so you may need to disassemble to fully inspect to eliminate as cause. The upper and lower intake gaskets, these can be cut while refitting intake, doesn't take much. IMT valve O-rings fail just like the X-Type ones did, another place to look.
As I mentioned to Donna, you may need to take to dealer or someone with SDD, or has a proper scanner than can monitor sensor data, or even read flight data, this will give insight as to what the car was doing when the fault occurred. I would suggest this before throwing parts at the issue, it can..... no it " will " be expensive, and time consuming.
Keep in mind, if you've been looking at one problem for so long, you start to get frustrated. May need to go back to square 1 and start over, you " may " have missed something. I've done this when I've been stumped, just a suggestion.
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