Why wont my OBDII monitors reset on my Ford Expedition?

SOURCE: 1979 ford ranger, did not pass smog

Oxygeb sensor failure or EGR not working, bolcked passages.

Go to autozone and get failure codes for free if newer than 1996.

Wayne Pennington

• 34 Answers
• Posted on Dec 03, 2009

SOURCE: I need to know what smog equipment the 1976 ford

None. Yes I said it right, None. Belive it or not in 1976 trucks were not required converters, air pumps and could run on leaded or unleaded gas. Man I've been doing this too long and I'm getting old.

SOURCE: p1401 manufacturer specific code

p1401 is your egr valve

SOURCE: 1998 ford expedition misses, ,shudders, replace

The coil is not seated correct or it has become bad also. These have a tendency to mess up on a regular basis. I use a di-electric grease on mine to help it from misfiring. I would take that #4 back off and re-seat it and see how it performs.

Testimonial: "Thanks, I'll try to reseat it and see. "

SOURCE: Check Engine Light on Yr2001 Ford Escape V-6 2wd.

If the engine has a P0305 DTC (Data Trouble Code) for a "cylinder 5 mis-fire detected", then the first thing to do is to do a compression test to determine if the mis-fire is actually being caused by a mechanical problem, or an electronic problem.

If the engine really does have low compression on the #5 cylinder then that is caused by a mechanical mis-fire and nothing electronic will repair it, and the most common causes for a mechanical mis-fire would be a burnt or bent intake or exhaust valve, a warped cylinder head or damaged head gasket, or a damaged piston. You can call around and find a repair shop that will do a "compression leak down test" if you want to know exactly what is causing the compression leak without any dis-assembly to the engine.