94 Grand Marquis - running rough

[frisbeeguy]

Hi,
It's showing codes # 172, 176, 634.

(I'm posting for a friend)

Anybody know what I should do first? He just got the car & doesn't know anything about it.
Thanks y'all

[slapntickle]

Not sure if you are asking what the codes are or where to start to correct the problem. This link should take you to the codes.

http://www.autozone.com/autozone/rep...00c152801e49d3

[frisbeeguy]

Thanks, just kinda wondering what to attempt first.
I was thinking of replacing the O2 sensors but that'll be expensive & may not solve the problem? (what is causing the sensor to throw a code?)
It's got around 90,000 miles on it.
Can the O2 sensors go bad without something else causing the problem?
Do I have to replace all 4?
Can I replace the 2 front ones? (b4 cats)
Thanks

[slapntickle]

172 indicates lean on bank 1, and 176 indicates lean on bank 2. I'm not convinced that it's the O2 sensors. Lean would mean that the car is running lean on fuel. I'm thinking that your not getting enough fuel to the motor. I would check the fuel pressure to see if you have enough pressure. Also, does the car run ok the first few minutes it starts? (Fords run on a closed circuit when they first start up for a few minutes. ) And does it run the same with the MAF unplugged? Is there any color to the exhaust or smell?

[frisbeeguy]

Originally Posted by slapntickle

172 indicates lean on bank 1, and 176 indicates lean on bank 2. I'm not convinced that it's the O2 sensors. Lean would mean that the car is running lean on fuel. I'm thinking that your not getting enough fuel to the motor. I would check the fuel pressure to see if you have enough pressure. Also, does the car run ok the first few minutes it starts? (Fords run on a closed circuit when they first start up for a few minutes. ) And does it run the same with the MAF unplugged? Is there any color to the exhaust or smell?

One million thank you's for this reply.
I'm good at doing things but really don't know squat...I've always wondered what running lean / rich means for instance.
I'll do a search on how to & try to check the fuel pressure later today - will post the findings afterwards.
It is hard starting - I don't know if there is any exhaust color / smell.
BTW...I have the utmost respect for good mechanics - they do hard, dirty, complicated work often with screaming, frustrated & broke car owners getting in the way. They definately earn their money.