1993 Ford Thunderbird engine starts to miss at 2500 RPM los

JIM WILKINSON

MEMBER
1993 FORD THUNDERBIRD

Engine Performance problem
1993 Ford Thunderbird 6 cyl Two Wheel Drive Automatic

car starts ok idles ok but get rpm around 2000 and car starts to miss and will not rev up. If you put the pedal to the floor the rpms will not top 4000. So onasseleration if you move pedal down then up it seems to start to go and as trans shifts and stays under 2500 rpms you can go as much as 70 to75 for 6 to7 miles then engine lerches and loss of power till you move pedal down and up you can resume your speed. II have disconnected my exhaust pipe left side it begins to miss at 2000 rpm hook it up and with right side disconnected same. So I ruled out left or right converters.I have new wire set plugs, fuel filter, no change.I AM STILL STUMPED? MAF SENSOR MAYBE? HELP!

1 Reply

DAVE H

MECHANIC
13,383 POSTS

While the PCM is in FMEM this could affect engine performance. You need to have your cars PCM read to locate where the fault lies?

COMPUTERIZED ENGINE CONTROLS
CONTROL UNIT
Powertrain Control Module (PCM)
PCM monitors engine operating conditions by input received from engine sensors. Control of output actuators determines fuel mixture and idle speed. For PCM location, see POWERTRAIN CONTROL MODULE (PCM) LOCATIONS table.
The engine control system consists of the PCM, relays, modules, sensors, switches and actuators. The PCM sends out electrical reference signals to engine sensors and then analyzes the return signals. The engine sensors supply the PCM with specific information, in the form of electrical signals, to determine engine operating conditions. In the event of a sensor or actuator failure, the PCM initiates an alternative strategy called Failure Mode Effects Management (FMEM) to allow the vehicle to maintain driveability.
The Malfunction Indicator Light (MIL) will remain on whenever FMEM is in operation. FMEM substitutes a fixed sensor signal and continues to monitor the failed sensor. If the signals from a faulty sensor return to within operating limits, the PCM will resume using the sensor'ssignal.