rscultho

I have a 2002 Taurus, 3.0L DOHC Duratec. Aprox 72K miles. Recently when coming home one night, the car starting running really rough and lost most of it's power. On the way home whenever I would try to accelerate, it sounded like the valves were pinging - the way they do when the timing is off. Additionally there were loud pops - they were intermittent - not consistent, like marbles striking the side of a wooden box. Idle was awful, steering wheel was shaking so much it felt like an old weed eater in your hands. I use mid-grade fuel.

Got the car home, read the codes. I got P1131, P1132, P1336, P1151 and P1152. I replaced both the Crankshaft Position Sensor and the Camshaft Position Sensor (CPK and CPM, 1136). Cleared the codes and ran it again till I got codes again. The P1336 went away, but the others remain.

I took the injectors apart and cleaned them. I replaced the fuel filter. I went ahead and put new plugs in. I took the exhaust piping off (Y piping) COMPLETELY including the main cat and inspected for blockages. I did not take off the bank 1 precat because it is made into the exhaust manifold. Tested airflow through the front precat (comes off with piping) and main cat. Airflow seems fine. Checked as many vacuum lines as I could for leaks - found none.

Additionally, in the past 6 months I have replaced the following parts for various reasons:
MAF
IAC
EGR valve
EGR recirc vacuum tubing
Idle control vacuum solenoid
Coil Pack
New Plug wires (premium wires, not cheap)
DPFE, including vacuum tubing on both inlet and outlet

The car runs really rough at idle, and in park I can rev it up. You hear the popping and the pinging. It sounds so much like the timing is off. When you try to drive it, it has little power, and the popping and pinging are very evident when you first apply the gas - when it is at the lower revs of acceleration.

I know the P113x codes deal with the bank 1 O2 senors, and the P115x codes deal with the bank 2 O2 sensors. I think the codes are indicating that the senors are not switching and are indicating an overly lean condition, which causes the PCM to tell the injectors to feed more fuel which then causes a rich condition in the cylinders.

Question 1: What is the likelihood of both bank 1 and bank 2 O2 sensors going bad at exactly the same time?

Question 2:Is there something, such as the fuel control regulator, that would cause all of this? If the engine is being starved for fuel, would that cause the pinging and popping? I know it would cause a loss of power...

Question 3: Could the O2 sensors being bad cause all of these conditions? I know they will cause loss of power, but what about the pinging and popping? Also, with codes on both banks, just seems unlikely that both would go bad at the same time.

Question 4: Is it possible that one of the cam's have slipped a tooth? I am leaning against this because of the codes for both banks. Doesn't seem possible that one cam would affect both heads/banks.

Question 5: Could I have blown head gaskets? I know that will cause a rough idle, but I have never known that to affect timing. Also, I have no oil in the coolant, there is no escape of gases into the coolant. And I don't think a blown head gasket will give me the fuel metering codes I am getting.

I am stumped. I have tried everything I know, except for replacing the O2 sensors, and I just don't think both upstream O2 sensors are gonna go bad at the same time. It just seems like there has to be something upstream that is causing this problem.

Sorry for the book - any help would be GREATLY appreciated!!

Johnny Mullet

DTC/HO2S Reference List:

HO2S-11 = DTC P1132
HO2S-21 = DTC P1152
Check intake air system for leaks, obstructions and damage.
Check air cleaner element, air cleaner housing for blockage.
Verify integrity of the PCV system.
Check for vacuum leaks.

I suspect you have a small vacuum or intake leak. CAREFULLY inspect all hoses to the intake and PCV.