Contour Enthusiasts Group Archives Forums General Troubleshooting P0174 - Searched

96 Zetek MTX 97,000

My contour has been throwing a P0174 forever.

When I get it back from the shop for the wheel bearing replacement I am determined to track down the cause.

Symptoms:

Erratic Idle - When very cold it climbs to 1500 to 2000k then dies. After some gas it will quick stalling out. Then at idle it will go through a never ending cycle of ~1200 RPMS slowly down to 750 then it jumps down to 500 and runs rough for a sec then repeats the cycle.

I am planning on using as much throttle body cleaner as it takes to eliminate a vac leak. If the cleaner enters the enginge through a leak am I looking for a decrease in idle or an increase? Also, will I be able to pick up a leak in the injector O rings this way?

Thanks in advance.

Bank 2 fuel/air ratio too lean. Fuel trim system is at the rich correction limit.

Have you had your fuel injectors cleaned lately? Possilbly a sticking injector?

Have you done that old trick of placing a long screwdriver tip on the injector and the other end to your ear? A sharp click is good, a light tap is "plugged and gummed", no click - no fuel.

If the "cleaner" enters a vac leak, the RPM should go up, but the PCM will correct for this quickly.

Hope this helps.

Most of the time, this code is cause by a vacuum leak. Check for a hissing sound in the engine bay. Or use the carb cleaner spray method (spray in the suspected areas and if the engine idle increases or decreases, that would probably be the leak). Check loose hose clamps for rubber hoses and check for broken or cracked hose lines too.

From TSB
P0174 - System Too Lean (Bank 2) The Adaptive Fuel Strategy continuously monitors fuel delivery hardware. The code is set when the adaptive fuel tables reach a rich calibrated limit.
Fuel System:
�· Contaminated fuel injectors
�· Low fuel pressure or running out of fuel (fuel pump, filter, fuel supply line restrictions)
�· Vapor recovery system (VMV)

Induction System:
�· MAF contamination
�· Air leaks between the MAF and throttle body
�· Vacuum leaks
�· PCV system concern
�· Improperly seated engine oil dipstick

EGR System:
�· Leaking gasket
�· Stuck EGR valve
�· Leaking diaphragm or EVR

Base Engine:
�· Exhaust leaks before or near the HO2S
�· Secondary air concern

Powertrain Control System:
�· PCM concern