About 6 months ago my truck started to develop a intermittent miss. It was minor and barely noticeable, shortly after noticing this i parked the truck due to hard times for about a month and drove my late gas saver. I started driving the truck again and that minor miss has turned into a HUGE problem. Ive done most of the obvious and im stumped. Ive changed all spark plugs first, then i changed all cops along another set of spark plugs, and all fuel injectors about a week after. This helped very little. The miss is so bad it jars the whole truck violently. Also noticed my abs light comes on for a couple secs and the speedo and tach drop to zero for a sec then goes back to normal. Ohh yeah the truck is a 2002 F250 5.4 auto 4x4 152000. Sorry I wrote a novel too.

 

No check engine light or codes?

Adrianspeeder

 

None since I changed all the previously stated. I took it a local mechanic and he checked for vacuum leaks and said he couldnt find any. Could the o2 sensors cause this? Reason asking i ran the truck with catalytic converter only for about a month but it gave no problems until a couple months after the exhaust was put back on. Oh and ive also cleaned the maf sensor and changed the fuel filter. Im also curious of how would i go about checking the egr valve to see if its working good?

Thanks
josh

 

Another question, could the pcv valve cause this? I know theyre relatively cheap but how do you check them for proper function?

 

For the EGR just remove the vac hose and attach abrout a 2 foot piece and apply vac to it. Or just suck on it, the engine should stumble when you do that, if it does you're good.

What were the codes you erased?

 

jgger, I removed the egr valve hose and the truck instantly dies. whats that a sign of? The codes were misfires on i think 3 of the cylinders and system to lean on banks 1 and 2. After i replaced coils sparks and injectors and cleared codes, they nor any other code have come about. Ive also done the coil by coil check with engine running to see if it was a faulty coil and at idle and around 1000 rpm they all made the miss worse.

thanks
josh

 

Did it die on it's own or when you applied vaccuum? If it was when you applied vac then the EGR is good.

The 1000 RPM makes me think you have a vac leak some place, which will also give you a 171/174 code. Check all your vac lines real good and also the PCV system. There is an elbow on the 5.4's that is notorious for going bad.

Good luck.

 

It died on its own as soon as i removed the hose. The local mechanic here told me that it sounded like a vacuum leak and he checked all the hoses and couldnt find any that was cracked or leaky and i also double checked just to make sure and didnt find any. Ill check them all again bc thats been a couple months ago and the crack or leak could have gotten worse. How do i check the pcv valve and know if its actually working?

 

put something in the intake tube to seal it shut (like a cup or bottle) and crank the engine, it should turn over a couple times and die. If it starts and continues to run then you have a vacuum leak

 

ok so i put a cup in the intake tube, cranked the engine and it ran for probably 30 secs then faded out and died. when i started the engine it sucked the cup further into the intake tube like expected and i would imagine it was sealed off from gettin air. where is the most common vacuum leak on these trucks?

Thanks
Josh

 

Most common is the PCV elbow behind the intake manifold.

 

Ok i checked the pcv elbow and its in pretty good shape. Is the pcv valve suppose to rattle alot? Ive notice when i rev it up on the downfall it rattles quite a lot. Would a pcv valve make any difference?