Tredeh

My 4.2 f150 has had the dreaded p0171 and p0174 codes for a few months. I figured it was an intake gasket, but decided to do a "smoke" test. I blew cigar smoke into a vacuum line, and the picture below is where the same came out. I'm a little confused on what to replace



Is that where the smoke would go out if there were no leaks? If so what should I check next to hunt these codes down? Any help appreciated

white89gt

You should have no leak there. I believe it's just a bushing in there. Did you try and spray carb cleaner right there while it's running?

The only way I think that would get fixed is to replace the throttle body.

Tredeh

tried spraying carb cleaner in it, nothing happened.

Tredeh

It may also be worth noting that my fuel pump sounds like its wanting to die. It doesn't start hard or sputter when driving, but the pump sounds bad. Given that it just makes noise, could that be the cause of the p0171 ad p0174 codes?
MAF has been cleaned as well. The PCV valve looks fine, but for 10 bucks I might replace it anyway

DaytonLax14

The carb cleaner trick is not good advice, nor is it a good trick. All it does is create leaks!

Tredeh

Bump. So does this mean its not a vacuum problem, but a fuel delivery problem? Fuel pump has been suspect for a while due to the noise.
It's also worth noting that when I remove the CE light, it stays off for 2-3 days before coming back on. So far it's been off for well over a week, which is a new record.

Tredeh

Awesome. A thread about drag racing a 4.6 gets 12 replies but I can't get a simple answer here about a mechanical issue. Sweet. Guess I'll have to try a few other forums.

Jbrew

Don't let the door hit yuh.

Tredeh

Don't worry I wont . Was just a little irritated, what's the point of this forum when you can't even get mechanical advice on a legitimate problem. Oh well.

DaytonLax14

Could be the throttle body gasket leaking