Horrible misfiring and stumbling...

[FrOsTyShO]

Last night my car backfired about twice, so i slowed down and took it easy. I wasn't driving hard, shifting hard ect. Today i tried to reset the computer to see if that would fix it. Didn't work. Then i took the intake manifold off and cleaned out all the plug wells and wires.(all are new). There was a little bit of coolant in the back three from when i blew a coolant hose off. Didn't help at all, maybe even made it worse. Then my check engine light stayed on steadily, so i pulled the codes, I got-
511-No power to PCM pin 1 or bad PCM (processor)possibly my lpm??
122- TP low (possibly grounded or open circuit)
114-IAT sensor out of range (new)
998-(R) Did not pass Key On Engine Off test yet (Get 111 in KOEO first)
(O) Transmission Electronic Pressure Control (EPC) solenoid/circuit fault

 

[AutoSHO]

Check to see if the chip is loose on the computer. Mine drove horribly when the chip worked a bit loose.

 

[FrOsTyShO]

Yup, i checked that, didnt seem to be loose. Thanks anyway!

 

[AutoSHO]

The only code there that sounds even a little bit like it would cause a problem is the Throttle Position sensor code. Have you tried putting the stock MAF in and removing the chip to see if that takes care of the problem?

 

[EHBOY]

Prolly not whats ailing your car but... if you got coolant in your plug wells when you blew off your hose... then your spark plug boots aren't sealing to your valve covers..... Culprit? Get the correct spark plugs.

Also, sounds like you could need new plugs anyways. Get Denso or Motorcraft.

 

[projectSHO89]

Remove the LPM completely and reset the system.

If the specified problems continue, verify battery power to PCM pin 1 (Y)(Hot at all times). If power is present, replace PCM. If not, troubleshoot power feed to PCM.

The reason for the 511 code will force the PCM into FFEM (998). You must resolve this before **** anything else. You cannot perform a KOER test with a 998 set, the computer will not allow it.

If the input voltage to the PCM is missing or otherwise not available, there will be no reference voltage to a variety of sensors, including the IAT and the TPS.

Steve

 

[FrOsTyShO]

The PCM is behind the glovebox, right? I have the correct motorcraft plugs in there and ford wires.

 

[FrOsTyShO]

Well i replaced the plugs and now it wont turn over. I'm sure i got the plug wires hooked up right, i got the diagram off here. Thanks tia

 

[Mr Anonymous]

Did you follow Steve's instructions above? If the PCM is faulty, the best most expensive plugs and wires in the world won't fix it.

Yes, the PCM is behind the glovebox. Follow Steve's instructions and let us know what you find.

 

[FrOsTyShO]

Checked the pcm, yellow wire has power, replace plugs with new autolite platinums, still didnt start. I had a hunch it was the TPS for some reason so i disconnected it and the car fired right up. Threw a new one in and everything is fine! thanks guys! thumb