How do I check a cam lobe being worn? I have a #5 cylinder issue, I've done everything, it never goes away or changes. 300K miles.

I am getting rid of this truck as I no longer need it. It is in very good mechanical shape. I am going to give it one last shot at repair just for my own ego. This truck takes my milk money on a regular basis. LOL I don't drive it much but I use it as a yard truck.

Heads are done, timing chain, injectors, cam position sensor, you name it, I checked it, proved it or replaced it. LOL

Help would be appreciated.

Also, what do I Have to remove to do the camshaft, if indeed that is the problem ? Please be easy. (Grill, RAdiator, condensor, water pump, valve covers, rockers, push rods, lifters........ I am thinking of giving this truck away even more now. LOL

 

I pulled this information from another post I did in 2011. Yes it has been a while, nothing has changed.

Heads redone 20k miles ago,
new timing chain
throttle body checked
replaced IAC - aftermarket -
MAF cleaned - wasn't dirty
Cam position sensor replaced
EGR tested every way you could check it, even blocked it off - all operations checks on it were good.
Replaced coil
replaced wires
replaced plugs with the correct ones
removed the plenum- checked gaskets
removed valve cover
checked all sensors
replaced lines on pcv valve-and pcv
replaced all injectors - tested injector fire signals from computer - all good
tested fuel pressure
DPFE ?? checked
compression checked 3 times, all around 180PSI,
smoke checked for vacuum leaks
hours spent under the hood looking around listening and checking vacuum lines for leaks, spraying starting fluid to check engine response....what we did not do. LOL

 

Remove valve cover.
Manually turn crank(remove spark plugs) and measure rise and fall of #5 valves, also look closely at the springs.

For a cylinder to fire as it should it needs 3 things
air/fuel in correct mix, fuel injectors, computer
Spark at the right time, CPS, Coil, Computer
Compression high enough to allow ignition by spark, rings, valves, timing chain but this would effect all cylinders.

What is the #5 issue?
I assume a misfire, but does it come and go, or only misses when warm, or cold?

Later 3.0l engines, 2003-2006 I think, had bad valve seats, they would recess and cause misfires

To replace camshaft you would
remove CPS
remove upper and lower intake
remove rockers, push rods and lifters
remove front engine brackets and main pulley
remove rad and A/C condenser
remove timing chain cover
remove cam timing gear and timing chain
remove camshaft, the rad and condenser need to be removed because camshaft is as long as the engine, so you need at least that much space in front of engine to slide it out.

You need to pull the engine out if you want to replace the cam bearings

 

The miss is constant and has only gotten worse. It is only #5 cyl. I did the heads 30k miles ago. They were recessed pretty bad. At the time I replaced the timing chain, the water pump was fairly new. I may check the cam.

 

And it missed before and after doing the heads??

 

The heads were bad and the engine was running very rough when I got the truck from my son. They told him the injectors needed to be replaced. I pulled the heads, the valves were into the heads by 1/4" at least. After I did the work, the engine ran fine but there was a miss I could feel at cruise speed, it was very slight and not easily detected. That is when I began to check with the use of scanners and such. As I changed parts, the engine ran better. The miss has grown progressively worse. The engine has been very rough at idle for 2 years. I don't use the truck much but I take it on the road to get stuff. It is my hack round truck but I like the size. Rangers are COOL !!

At present, the tail pipe is black internally, the engine runs very rough and my mechanic friend last month put the scanner on the engine. The scanner showed the output of #5 to be very low if anything at all.

I did compression tests - static and with the engine running. I recorded all that. Compression was good.

I thought my mechanic buddy looked under the valve cover to check the cam.

This sun of a gun is going to get ejected - given away real soon. LOL I just got my 2003 Chevy back from my son and it is PERFECT.