check engine light with codes p0174 and p0175

[jvillerauder]

my check engine light came on with the codes p0174 and p0175. the computer tells me that its lean in bank 1 and bank 2. couls someone tell me what exactly this means and how to address it please. ive also noticed that it runs rough at idle. i would appreciate any help with this. thanks

[musclemerc]

Sounds like a vacum leak. Check the main PCV tube, the rubber fittings will crack over time. You can also check the EGR valve and make sure it's not stuck in the open position.

[fastblackmerc]

Sounds like a vacum leak. Check the main PCV tube, the rubber fittings will crack over time. You can also check the EGR valve and make sure it's not stuck in the open position.

Definitely sounds like a vacuum leak. That would cause a lean condition.

[jvillerauder]

ok ill check that. funny thing also happens with the ac. if i hit the gas hard my ac starts to blow out the defrost and if i let off the gas it comes back through the other vents. also pumping the brakes helps with it too. i wonder if it could all be interconnected? thanks for the info btw.

[musclemerc]

Ummmm. All those use vacum to work. You should take your MM to the dealer so it can be fixed by a certified technician.

[LordVader]

May also be an exhaust leak (check the gaskets).

[fastblackmerc]

ok ill check that. funny thing also happens with the ac. if i hit the gas hard my ac starts to blow out the defrost and if i let off the gas it comes back through the other vents. also pumping the brakes helps with it too. i wonder if it could all be interconnected? thanks for the info btw.

Classic vacuum leak symptoms.

The heat - A/C system is a "fail safe" system. If there is a loss of vacuum the heat or A/C comes out the defroster vents to keep the windows clear.

I'd also check the vacuum reservoir, under the hood, left side, square box, mounted on top of the plastic inner fender, has one vacuum line going to it.

[musclemerc]

May also be an exhaust leak (check the gaskets).

FYI the MM comes stock with some of the best exhaust gaskets on the market. Alot of us running headers reused the stock gaskets because they are superior to aftermarket options. The chances of having an exhaust leak is slim at best. Not saying it cant happen but it's slim.

[fastblackmerc]

FYI the MM comes stock with some of the best exhaust gaskets on the market. Alot of us running headers reused the stock gaskets because they are superior to aftermarket options. The chances of having an exhaust leak is slim at best. Not saying it cant happen but it's slim.

Especially if you've never had exhaust work done.

[RF Overlord]

I agree you have a vacuum leak. Having lean codes on both banks along with a rough idle are classic symptoms of un-metered air getting in.

Your A/C problem may be related to this, or you could have the infamous EATC module o-ring issue. Fix the code and idle issues and if you still have the A/C problem, read this (http://www.mercurymarauder.net/forums/showthread.php?t=36922).

[knine]

Is this any help? http://www.p71interceptor.com/eatcswap/selftest.html

[fastblackmerc]

Get the check engine codes fixed before looking at the possible EATC issue.

[jvillerauder]

i checked the hose fvrom the pcv and it had a small hole in it so i replaced it and the engine runs good now. as far as the ac it still does the defrost thing but not nearly as often. btw i had to bypass the vacuum line for a direct line to the vacuum line near the glove box as i was having the ac problem last summer in south Florida where ac is a necessity. i had already changed the o rings in the eatc and it still went out the defrost vent. when i bypassed the eatc it blew out the other vents except under hard throttle. i will now check all my vacuum lines and see where it leads me. thanks for the help guys i do appreciate it.