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View Full Version : Threw 4 codes, what could it be?



Vostok
07-07-2011, 04:39 PM
I've had a couple symptoms.

1. When I start the car in the morning before work or anytime it sits for 4+ hours it bogs until it has idled for a little while and/or I give it gas and it smooths out for the entire duration of the drive and runs completely normal lacking no power at all when under load.

2. In the 35-45 MPH range under no load (before OD kicks in) there is a very slight bucking (not something most people would notice) and the level/intensity of the bucking increases if the A/C is on.

3. MPG sucks ass. Been getting like 14-16 MPG on tanks of gas that are mostly highway.

I've been trying to isolate it for a while now but could not figure it out due to no light and many possibilities.

Threw 4 codes all at one time yesterday after not having a check engine light for many months.

P0171 - System Too Lean, Bank No. 1

P0174 - System Too Lean, Bank No. 2

P0102 - MAF Circuit Low Input

P0113 - IAT Circuit High Input

I'm like 80% sure it is not the following issues due to testing

- Vacuum leak
- Fuel pressure
- Dirty MAF
- Dirty IAC
- 100% sure its not the plugs

Do our MAFS just plain go bad after a while beyond cleaning?

Don't really know much about the IAT, that one troubles me as I know its somewhat of an uncommon code to see which could be a good thing or a bad thing...

Help :alone:

RacerX
07-07-2011, 05:35 PM
IAT is part of the maf sensor. Outer two wires on the harness. All those codes can be caused by a bad MAF sensor. Can you pull the harness and make sure all the contacts are clean?

Vostok
07-07-2011, 07:58 PM
IAT is part of the maf sensor. Outer two wires on the harness. All those codes can be caused by a bad MAF sensor. Can you pull the harness and make sure all the contacts are clean?

Used the torx drill bit and removed the MAF from the intake and cleaned every nook and cranny of it very thoroughly with CRC MAF cleaner about 15 minutes ago. Took it for a drive, light bucking is still present. Will not know if it has any effect on the cold start bogging / MPG until tomorrow.

RacerX
07-07-2011, 08:38 PM
Did you unplug the harness connector from the sensor? Leave the sensor in the maf housing and check the male and female side of the harness connector for any sign of corrosion, etc. The connector looks like the one on the right in the pic. Look for any broken wires too.

http://www.mercurymarauder.net/gallery/data/579/medium/Diablo_connectorpin_204.jpg (javascript:;)

Vostok
07-07-2011, 09:47 PM
Did you unplug the harness connector from the sensor? Leave the sensor in the maf housing and check the male and female side of the harness connector for any sign of corrosion, etc. The connector looks like the one on the right in the pic. Look for any broken wires too.

http://www.mercurymarauder.net/gallery/data/579/medium/Diablo_connectorpin_204.jpg (javascript:;)

Of course I unplugged it :P Did not see any broken wires or obvious corrosion.

MAF sprayed the harness connector as well.

justbob
07-08-2011, 05:20 AM
I have an extra you can try out. Contact someone, anyone, whoever for my number :) I'll be home around 4:30 and all weekend.