I was told i had a cracked head or a bent valve. i took it in because the engine has a intermitten missfire in it, they wanted to do a cylinder leak down test but they wanted alot of money for it. i told them that i will do it myself so this weekend i pulled the plugs and did a compression test on all the cylinders and then a leak down test on the lowest one and the number six which they said was bad. on the drivers side bank they where at 215 for 5,6,and 7 and 8 was at 218. then on the passenger side 1 was at 212, 2 was at 202, 3 was at 216, and 4 was at 210. the chiltons manual said that as long as the lowest cyl. was within 75% of the highest it was ok. I was concerned about number 2 being so much lower than the others so i did a leak down test and i didnt hear anything out of the exhaust or intake and i didnt get any bubbles out of the coolant reservoir. I also did number 6 and it was the same thing. the only place air came out was the oil dipstick and it was the same for both. I didnt actual calculate the loss of air i just plugged it in and listened for air. from those results i think the engine is good. does anybody else hae any thoughts? now that i think the engine is good the problem still exists so does anybody else have any ideas as to where the problem might be? could it be the camshaft variable timing oil sensor? how do i get that out of the valve cover? thanks for any help you can give me.

 

What year truck and what motor? How many miles?

 

Did you replace the spark plugs while you had them all out?

 

its a 04 5.4 triton 3 valve. I did change the plugs and they have about 100 miles on them. i also have replaced the coil boots and wires. I have done a vacume leak test on it and i had ford do a power balance and an injector leak down test. they all checked out. I havent gotten into any sensors yet or the pcv valve setup yet. I realy don't think its the engine because it never runs exactly the same every time. sometimes it idles extreamly rough, sometimes it has a very noticable intermitten miss, and sometimes it feels like it runs realy smooth with a miss here and there. if it had a cracked head or a bad valve i figured it would run the same every time. another possibility is that i had the muffler cut off because it was rusting out and just a solid pipe welded in there. could that cause it to run bad. it ran fine after i did it and i noticed it about 10,000 miles later.

 

Are you getting any misfire codes? These engines are somewhat problematic with respect to intermittent misfires and rough idle condition. What does your TB look like? After you changed the plugs did any of the COP or injector electronic harnesses break a tab? I've had a few back out on me causing misfire and rough idling.

There's a standard course of treatment I prescribe for people with rough idle:

1. Clean the TB
2. Change the filters, air and fuel
3. Change the plugs
4. Run some seafoam through a vacuum line
5. Use 3/4 of a can of Seafoam in your next full tank
6. Replace COPs of offending cylinders in the event you get a P030x code

If none of that works you can try getting the PCM reflashed, some have reported that it solved their issues. Whereas others solved the problem by replacing the motor mounts (only for rough idle without a mis).

 

that sounds like a plan. what are the chances it could be one of the sensors or solenoids that work in conjunction with the timing? I have already sucked seafoam up and that is what made it worse. also i pulled the intake manifold off for a IMRC fault and when i did i cleaned the holy heck out of the TB. and no there are no codes whatsoever. does my compression test look adequet or should i be worried about the 202 psi? also if i where to get the comp. reflashed do i have to take it to ford for that or can anyone with the program do it, as long as they have the know how. it is supposidly out of date also with its programs i guess, would that have any effect. I realy feel like i am just not getting full electric potential to the plugs and that is making it run rough and missfire, could taht pe possible and not pick up on a power balance? thank you for the advice I have millions of questions as you can tell so any answers would help alot. thank you!

 

You can also try cleaning the VCT Solenoid, there's one on each valve cover. I've not done this before but I've read that its easy and provided good results. Also, what oil and filter are you using? If you think your plugs or lack of power to them is a possibility buy new boots. The ones at Oreilly's are about $5 each. Heck, you can get all new COPs for just over $100 on ebay. Accel brand I believe.

You'll need to go to the dealer for a reflash, probably around $85 (est 1 hour of labor...which is BS).

 

I already put new boots on there from napa and they did make the idle alot better, but there still is a missfire. I think i will try to get a reflash done and also get the computer completly updated. I also want to take it to another dealership to get a second opinion on it. I am using valvoline 5w20 full synthetic and a motorcraft filter. I do also like your idea on the new COP's I havent swaped them out because i thought it would be a 400 dollar bill, so i might also try that. what oil do you run in yours bridge? i try changing it at around every 5K to 6K depending on the use! I tried throwing some lucas addative in there incase i had a sticking valve, but it didn't help at all. anyways i am almost to the point i am just gonna live with it until something major goes out and or the light comes on so i can get an idea what is going on. thanks for all the help you realy know your stuff!

 

I run Pennzoil Platinum Synthetic 5w-20 at 5-7K miles change intervals. Good luck with the reflash!

 

thanks for all the help i will keep ya posted on my findings.