Body Tech.

Tried to get as close as i could get with the year of my truck on the categories.. My 05 f150 4.6 2v. suddenly lost number 3 cylinder about 3years ago i finely made time to work on it on my weekends. did a compression test all cylinders but number 3 are at 165 my research says this is good compression for a 4.6 with over 2k.number 3 was at 30psi. i pulled the "heads" number 3 was cracked in the exhaust port pulled the piston and it was shot where steam/coolant got into the rings. i replaced that piston and found to used heads that i retooled the valves and installed new lifters with shorty headers with glass packs installing the 02 sensors in them . now it's all back together and all cylinders are at 165 to 170 psi . i replaced all the injectors and coils. cam crank and thermostat sensors. on start up when cold it seems to run decent with a load on it with foot on the break. but when i test drove it it pops and throws a cod p0172 and has no acceleration. i made sure when i put it in timing that the marked links on the chains was line with the marks on the cam and crank sprockets/ gears and has no vacuum leaks. i'm at a lose. do i need to recheck the timing ?

Jbrew

A lot of work. This isn't a 05 forum, but can't those drive by wire throttle bodies get flaky as well ?

2008__XL

You didn’t get too close. You posted in the 97-03 section. The 04-08 section is right above.

You’d get more help there.

BareBonesXL

That's a rich code. Those are tough, they seem to have several odd causes. I don't think that cam timing is one of them.

https://www.obd-codes.com/p0172

https://www.f150forum.com/f4/