I have a 1998 ford f150 with the 4.6liter. Very 1 or 2 years the dreaded check engine light comes on, and when I scan for the code, it’s always the same. P0174. I fight like hell and finally find the problem and fix it, but this time I can’t figure it out. I have done all the usual checks and all is good.
I do have a leak at the driver’s side exhaust manifold, could this set off this code?
signed: the frustrated.
I have done all the usual checks
it would be really helpful if you could tell us what checks, so we're not telling you to do things you've already tried.
I do have a leak at the driver’s side exhaust manifold, could this set off this code?
Absolutely it could. The definition of your DTC, P0174 ( https://www.obd-codes.com/p0174 ), is "System Too Lean".
Lean means too much oxygen in the mixture, as detected by the O2 sensor in your exhaust.
A leak in the exhaust introduces air into the exhaust stream that shouldn't be there.
Edit your post, add a space between the "4" & the ")" at the end of the link, says the hyperlink doesn't work. Otherwise 100% agree
Thank you @nta98
Corrected.