95 Crown Vic intermittent rough idle coding p0171 and p0174 - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars
Ford Forum Ford Forum

» Auto Insurance
» Featured Product
ยป Wheel & Tire Center

Go Back   Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars > Ford Cars and PAG Vehicles > Ford Crown Victoria | Mercury Marauder | Grand Marquis | P71
Register Home Forum Active Topics Photo Gallery Auto Loans Garage Mark Forums Read Auto Escrow

Ford Crown Victoria | Mercury Marauder | Grand Marquis | P71 Forum for discussion of the Ford Crown Victoria, Mercury Marauder, Mercury Grand Marquis and P71.

FordForums.com is the premier Ford Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools Display Modes
Old 12-01-2006, 09:18   #1 (permalink)
Registered User
 
Join Date: Dec 2006
Posts: 3
confused 95 Crown Vic intermittent rough idle coding p0171 and p0174

Hello Ladies and Gentlemen,

This is my first post in this forum so hello to all of you. I have a 1995 Crown Vic LX with 175k miles on it.

I first noticed the intermittent problem as a single or double clunk when it shifts from 2nd to 3rd and from 3rd to overdrive. I read the engine codes and they were P0171 and P0174 which are the lean condition for banks 1 and 2. Also spit out a P0307 (Cylinder 7 misfire) a few times.

I replaced the fuel filter as it had been in there quite a while. No change. Also had the tranny pan and torque converter dumped and new filter as fluid looked to be a pale pink with slight yellow cast. Bottom of tranny pan was very clean. Also added Lubegard Red. Not much improvement but thats ok cause I wanted to have it changed regardless.

Found nasty looking thick coolant in plug holes 1 and 3 from previously leaking thermostat housing. Cleaned out all plug holes (fair amount of dirt in all) and cleaned boots thoroughly. Still throwing the cylinder 7 misfire occasionally though. Gently cleaned MAF sensor with Windex spray and blew dry. Now the engine runs as smooth as silk most of the time and the tranny shifts so smoothly you can't tell except from egine rpm. However a couple of times a day it starts running rough again for a few minutes, looses about 1/3 power and throws both lean codes... and clunks between gears.

Got a Actron fuel pressure gauge and it was 31 psi engine running and the same with engine off and key on. Read it two days later and it was 40 psi key on and 31 engine running. Possible bad fuel pump? I have been trying to catch it in the rough idle mode and check pressure but have been unable to so far.

My questions would be how long do fuel pumps normally last and is 31 psi marginal for running pressure? Since the car is so old and has so many miles on it what sensors if any might i look at replacing? Four months ago it threw some egr codes for a few weeks but none since. Any other ideas?

Thank You,
Bob
Bob Wells is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 12-04-2006, 18:02   #2 (permalink)
Police Officer/Rescue Tec
 
ryoder's Avatar
 
Join Date: Mar 2005
Location: Morganton,N.C.
Age: 51
Posts: 274
Re: 95 Crown Vic intermittent rough idle coding p0171 and p0174

Are the misfires always on the same cylinder?
ryoder is offline   Reply With Quote
Old 12-04-2006, 22:20   #3 (permalink)
Registered User
 
Join Date: Dec 2006
Posts: 3
Re: 95 Crown Vic intermittent rough idle coding p0171 and p0174

Quote:
Originally Posted by ryoder
Are the misfires always on the same cylinder?
Yes, the misfires were always for cylinder #7. In the past three days of light driving there haven't been any misfire codes at all. Only P0171 and P0174, the lean codes occuring 4 times, always together. And they always coincide with a roughness of the engine and some loss of power and what is now only a small clunk in the tranny when shifting. The rest of the time power is good, engine smooth and tranny shifts are almost undetectable under light acceleration and clean and crisp under brisk acceleration.

I wish I knew of a relatively inexpensive 0 to 60 or 100 psi fuel pressure transducer I could plumb into the injector rail and connect to a dmm. That way I could keep an eye on the pressure. Maybe a stock transducer that has a simple analog output made for another car that I could find at Checker?

One other observation. I traced the spark plug wiring from each of the two spark coils to the plugs and I cannot for the life of me why they don't coincide with the shop manual and yet the engine runs so smoothly most of the time??? I haven't replaced the wires. I will investigate further.

Thanks,
Bob
Bob Wells is offline   Reply With Quote
Old 12-05-2006, 08:12   #4 (permalink)
Registered User
 
Join Date: Dec 2006
Posts: 3
Re: 95 Crown Vic intermittent rough idle coding p0171 and p0174

Quote:
Originally Posted by ryoder
Are the misfires always on the same cylinder?
Yes, the misfires were always for cylinder #7. In the past three days of light driving there haven't been any misfire codes at all. Only P0171 and P0174, the lean codes occuring 4 times, always together. And they always coincide with a roughness of the engine and some loss of power and what is now only a small clunk in the tranny when shifting. The rest of the time power is good, engine smooth and tranny shifts are almost undetectable under light acceleration and clean and crisp under brisk acceleration.

I wish I knew of a relatively inexpensive 0 to 60 or 100 psi fuel pressure transducer I could plumb into the injector rail and connect to a dmm. That way I could keep an eye on the pressure. Maybe a stock transducer that has a simple analog output made for another car that I could find at Checker?

One other observation. I traced the spark plug wiring from each of the two spark coils to the plugs and I cannot for the life of me why they don't coincide with the shop manual and yet the engine runs so smoothly most of the time??? I haven't replaced the wires. I will investigate further.

Thanks,
Bob
Bob Wells is offline   Reply With Quote
Sponsored Links
Advertisement
 
Reply

  Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars > Ford Cars and PAG Vehicles > Ford Crown Victoria | Mercury Marauder | Grand Marquis | P71



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Powered by vBadvanced CMPS v3.2.2

All times are GMT -7. The time now is 03:13.



Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO 3.6.0
Garage Plus vBulletin Plugins by Drive Thru Online, Inc.