Hey all,

My 2000 f150 has about 144,000 miles on. It's ran fine after I changed the plugs, then it started acting up again and I pulled the codes. Changed the coils, again ran fine for about a month and acting up again.

I've replaced the:

fuel filter
air filter
iac valve / bypass valve
plugs
ignition coils

What do I try next?

 

Vacuum lines all look ok as well. I did the carburetor cleaner test on them and physically checked everyone I could fine, elbows and lines. I'm stumped here....

 

You would be suprised how fast the coils go out. Ive personally gone through about 40-50 in the last 3 years.

 

Quit buying junk coils.

 

Its something else. Ive tried motorcraft, accell, and grantatelli or however you spell it. I dont mind, I just carry a spare in the glovebox

 

makes me glad I don't have COP

 

Be glad, very glad.

 

Thanks for the replies! The check engine light finally came on again so I'll pull the codes this afternoon and post the results.

That's gonna suck to have to buy more coils if that's what it is. I did buy cheap ones though on eBay.

 

Buy Acell coils, the yellow ones. Best Ive owned and opened the top end up to a noticable amount. Its like $240-250 for 8 or $64 each. They have a lifetime warranty too, Ive returned 1 and they just swapped it out. That all depends on your parts store though.

 

Well the code it gave me is:

P1151 = Lack of HO2S-21 Switch, Sensor Indicates Lean

"This particular DTC article refers to a P1151 trouble code on Ford vehicles. This does not apply to other makes of vehicles. A Heated Exhaust Oxygen (HO2S) sensor indicating lean at the end of a test is trying to correct for an over-rich condition. The test fails when the fuel control system no longer detects switching for a calibrated amount of time."

I'm gonna get a DMM and just start checking sensors. idb2328 posted an awesome thread about doing that here: https://www.f150forum.com/f6/egr-evap...ps-iat-243366/