Mechanics

CAR SHAKES OR JERKS FOR A SECOND

1997 Ford Expedition

Shakes or Wobbles problem
1997 Ford Expedition Four Wheel Drive Automatic

When driving the car, usually around 40 mph, and then pressing on the gas pedal to go faster, the car shakes for a second then goes to the next gear to go faster. As of right now the Check Engine Light is on and we have a P0446 error. Now just recently after this shaking, the light started blinking for about a minute then just went back to just staying lit. Do you think the shaking could have something to do with the error code we have? And if not what could it be? The light has been on for a long time and has never blinked before until now. We are trying to figure out the P0446 problem right now.
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Jennifer618
March 13, 2010.



Continuous Memory Diagnostic Trouble Code (DTC) P0446 or P1450 indicates that Self-Test has detected the Evaporative Emission Control System has excessive fuel tank vacuum. Also, a DTC P0446 indicates a vent control malfunction.

Possible causes: EVAP canister purge outlet tube (EVAP canister purge valve to EVAP canister) blockages or kinks.
EVAP canister tube (fuel tank to EVAP canister) blockages or kinks.
Fuel vapor elbow on EVAP canister contaminated.
Restricted EVAP canister.
Canister vent (CV) solenoid stuck closed (partially or fully).
Plugged or contaminated CV solenoid filter.
EVAP canister purge valve stuck open.
Fuel filler cap stuck closed (no vacuum relief).
VREF circuit open in fuel tank pressure (FTP) sensor.
Damaged FTP sensor.
Note: If the EVAP canister-CV solenoid and fuel tank assemblies are not accessible to perform the following step, GO to the Powertrain/Engine Group, Evaporative Emissions Section in the Workshop Manual for removal procedures.

Check for kinks or bends in the fuel vapor hoses/tubes (EVAP canister purge outlet tube and EVAP canister tube).
Visually inspect EVAP canister inlet port, CV solenoid filter and canister vent hose assembly for contamination or debris.
Check CV solenoid filter for blockage or contamination.