Hi! My name is reece. I have a 2008 Ford F150 4.6L and its been broken down in our shop for quite some time now. It started acting funny when I could not get the truck to do over 80kmh. Slow acceleration, and a horrible shaking when it idled. Eventually it was undriveable since I could go above 50kmh anymore. From looking online we replaced the plugs and coils. We removed the intake to find the gaskets were shot so coolant was leaking into the spark plug tubes which could've been the cause of a misfire. Fixed that. Still the same. We replaced the egr valve and dpfe sensor because we keep getting the P0402 excessive egr flow code. Still no luck. My dad is a journeyman hes just not too familiar with newer trucks. Does anyone have any suggestions? Or have dealt with this before? I need it fixed soon! Thanks, reece!

 

1. Have you checked the fuel pump driver module for any obvious corrosion damage?

Fuel Pump Driver Module- Check yours!! - Ford F150 Forum - Community of Ford Truck Fans

2. Also, check the throttle body and MAF sensor for cleanliness, as well for any air leaks between the MAF sensor and TB.

http://www.fordf150.net/howto/clean-...low-sensor.php

http://www.fordf150.net/howto/throttlebodyclean.php

3. Possible vacuum leak somewhere?

 

The converters could be damaged from the misfires. Loosen the exhaust at the manifolds and see if it runs better.

 

Thanks alot guys! By loosening the exhaust before the cats we found out the cats were plugged. Problem solved. Thanks again guys!

 

Glad you figured it out. Depending on the amount of damage to the cats there could be chunks of material in the muffler too.