1999 Ford Expedition - Check Engine Light

[rogersauto17]

The computer is giving us two codes p1151, p1131. It will go into closed loop after clearing kam memory. Only for about two min. and then go back to open loop.

The Vehicle runs good, but bad gas mileage. Change the mass air and took care of it for one day. Can anyone give us some help on what to do. We have had the Vehicle back three times. We had Ford reprogram the computer and it did not help it.

[ricmorin]

Those are lean codes. Something is causing the engine to run lean. This could be anything from a PCV valve, purge solenoid, intake gasket, etc. Smoke test or propane test for vac leaks.

Just thought of this, the PCV line where it plugs into the back of the intake fails often...please check.

[brianp87]

Maybe a vac leak? Y did u replace maf? Was it a rebuilt aftermarket?

[steven kiser]

THERE HAS BEEN AN UPDATED INTAKE FOR THESE..................

[rogersauto17]

The o2's are triing to lean it out , because it is running to rich. It is using a lot of fuel. We have checked for leaks also. The 1st time we hooked up to it, the codes come back to o2 sensors.Can you think of anything else it could be.

[ricmorin]

What are the O2 sensor voltages stuck at?

[liljoe]

I think you need to reset the adaptive stratagy by disconecting the battery for 5 mins, I had this problem one time. It came in with the opposite codes and after repairs these codes came in and I had to reset the adaptive stratagy. Found this somewhere else: The BARO frequency reading on the scan data, at sea level, is typically 156 Hz, plus or minus 4 Hz, and will go down by about 3 Hz for every 1000 ft. above sea level. The BARO reading on scan data is NOT a sensor reading, but rather it is a calculation of vehicle elevation that is made by the Powertrain Control Module (PCM). The PCM calculates BARO mainly by looking at the MAF sensor reading at high throttle openings, and comparing the readings to base sea level readings that are stored in internal memory. As such, just cleaning or replacing the MAF sensor will NOT change the BARO reading. The vehicle must be driven at high throttle openings for the BARO reading to recalculate, or it can be reset by disconnecting the battery for about 10 minutes, or performing a Keep Alive Memory (KAM) reset using a scan tool. Just clearing codes does NOT reset the KAM. Hope this helps out.

[brianp87]

Maybe a vac leak? Y did u replace maf? Was it a rebuilt aftermarket?

[steven kiser]

The computer is giving us two codes p1151, p1131. It will go into closed loop after clearing kam memory. Only for about two min. and then go back to open loop.


i'de be looking towards a vac leak or an air intake leak after the maf. i think that these have an issue with the rubber air intake tubes leaking. i've had cracked intakes causing these issues. with the scanner watch the front 02 readings and spray carb cleaner around the intake. you can use propane as well but i find the carb cleaner will make the 02's react in a mire defined manner. be careful not to set the engine on fire because there is an open spark. make sure the pcv is functioning properly. take oil cap off and see how much suction there is. if it's a good strong one that makes a slurping noise when you pull your hand away it's to much and either the pcv is bad or you have an internal leak. if the manifold is determined to be bad see f this one is effected by the intake modification up date. the egr runners are modified (this may be the problem) we've done many of these and some don't come with the new bolts. you need new ones. if they're not in the box the old ones can be cut to work.