I've got a misfire on cylinder 3 (p0303) and a too lean on bank one (p0171) on my 2006 F250 with 188K miles. The vehicle runs roughly both in idle and while running but it constantly fluctuates and will run smoothly for a second or more and then revert back to running roughly.
I've already swapped out the spark plug
, coil, and fuel injector
with components from other cylinders but the misfire does not follow any of the components. I put a light up spark plug tester on the plug #3 and it blinked consistently and steadily. I just did a compression test using the harbor freight quick-connect compression tester (#95187) which supposedly gives low readings and I got a reading of ~148psi on a cold engine
I also sprayed some water around the outside perimeter (but not inside perimeter because it is too inaccessible) of the intake manifold since someone suggested that but it didn't disturb how the engine runs like it's supposed to if I have an intake manifold leak.
I sprayed starter
fluid around the intake and nothing happened. I also put a noid light on the fuel injector plug and it blinked regularly like it's supposed to.
I should also mention that the misfire happens less when the engine is cold and gets much worse as the engine warms up.
FYI, when I first got this vehicle, it had numerous error codes.
P0011 - camshaft
1 timing over advanced
P0012 - camshaft 1 timing over retarded
P0021 - camshaft 2 timing over advanced
p0300 - random multiple cylinder misfires
P0303 - cylinder 3 misfire
P0304 - cylinder 4 misfire
P0340 - camshaft position sensor 1
P0345 - camshaft position sensor 2
P0430 - catalyst efficiency below threshold
To fix these errors I've done a lot of work so far. I cleaned up all the plugs and coils - some of which were actually rusty and I think a coolant
line was leaking onto coils 3 & 4. Installed new camshaft sensors. Swapped vct solenoids and found that the error codes followed vct #1. I've ordered a new vct solenoid but am still waiting for delivery. The catalytic converer is no doubt shot from burning off too much unburned fuel but that's not important.
Here is a picture I took from my phone based OBD scanner while in park with a warm engine. You can the little surges in fuel and fluctuations in RPM. I'm not sure if those little surges are due to the cylinder finally firing or if there is another cylinder that's stuck open sometimes.
So if you could provide me any help with this problem, I would greatly appreciate it.