system too lean!!

[gatlandc]

For about 5-6 weeks my car has been complaining about system too lean (diagnostic codes P0171 P0174) . After reading this forum I decided to replace to two front O2 sensors but the codes came back the very next day. Later that same day the cause became very obvious. A massive vacuum leak! When I went to start the car it just wouldn't run. It would cough, wheeze, scream, fart, whistle, groan, snort and die with a lough sigh. These wonderful wild beast like sounds were the result of the crank case gas recovery hose breaking off at the intake manifold. That opened a 19mm hole straight into the manifold, with all this fresh air bypassing the MAF sensor the computer just didn't know what to do and was overwhelmed. It took only 10 mins to replace the rubber connector hose with a piece of old heater hose and I'm back running like a baby. Yet again I have been stranded by the failure of a $2 part. Thanks Ford!

So if you have one of these diagnostic codes check the short connecting hose of the manifold which is probably the easiest thing to see under the hood.

[Limited360]

For about 5-6 weeks my car has been complaining about system too lean (diagnostic codes P0171 P0174) . After reading this forum I decided to replace to two front O2 sensors but the codes came back the very next day. Later that same day the cause became very obvious. A massive vacuum leak! When I went to start the car it just wouldn't run. It would cough, wheeze, scream, fart, whistle, groan, snort and die with a lough sigh. These wonderful wild beast like sounds were the result of the crank case gas recovery hose breaking off at the intake manifold. That opened a 19mm hole straight into the manifold, with all this fresh air bypassing the MAF sensor the computer just didn't know what to do and was overwhelmed. It took only 10 mins to replace the rubber connector hose with a piece of old heater hose and I'm back running like a baby. Yet again I have been stranded by the failure of a $2 part. Thanks Ford!

So if you have one of these diagnostic codes check the short connecting hose of the manifold which is probably the easiest thing to see under the hood.


Your car is 10+ years old... Rubber hoses fail... Plastic deteriorates from heat cycles...

Lean codes would of pointed to a vac leak for me. Should of had an elevated idle from that issue as well however. Maybe the IAC learned the error out however.


Sent from my iPhone using Tapatalk so I may sound retarded.

[mnrauder]

I've been fixing this error one hose a time.

[gatlandc]

Yeah I've been replacing a lot of stuff too and I'm still under 100k. It makes me wonder is there a list on this forum of the top ten Marauder /Crown Vic /Marquis faults?

So fare I have replaced or repaired:
Lighting control module
EATC O-rings
Oil filter stand gasket
Window switches
AC clutch relay
Crank case gas recovery hose

What is next???

[SpartaPerformance]

Could be possible manifold vacuum leak.

[Motorhead350]

What hose is this?

I have been getting these codes all summer, but not in winter.

The codes will come in winter if I turn the car off and on in a short period of time. If normal on and off, the codes stay away for months.

Same issue as you?

[Kennyrauder]

Quit whining about minor issues.Just remember your vehicle is over 10 years old...what can you expect? Ask long term BMW or Mercedes owners what they have been through.You are way ahead in reliability, & mtce. costs.

[Motorhead350]

So in other words you do not know.