Ok heres the deal. 2001 Dakota Sport CC 4x4, 4.7L engine...top was rebuilt by the stealership under the previous owner. Ever since it was released from the local *clueless* 5 Star, it has had a bad tapping/knocking/pinging (and whatever other description you would like) in the engine bay. I can't pinpoint exactly where within the engine its comming from. While standing next to the truck with the hood up, it sounds like the intake on the passenger side.
Now I have read a zillion posts on this and I know it seems to be a somewhat common thing with these engines. With this in mind, I have read possible causes being:
1. Possible collapsed Lash adjuster.
2. Valve leaking down while sitting for a while.
3. The infamous "Belly Pan Gasket."
4. Noisey-clogged Injectors
5. Ignition Coils.
6. Loose or improperly adjusted "Rockers."
7. Exhaust Leak.
8. Flex bolts backing out????? (yeah read a post that said it was the cause)
9. Timing Chain.
With all these various possibilities, I am attempting to isolate the culprit. When I first bought the truck, this thing rattled like a Diesel. Since then, first thing I did was an oil change. It seemed to make no difference.
Symptoms: Cold start in the Morning....tap tap tap tap tap....I let the engine warm up at least 2 minutes, carefully watching the oil pressure gauge and keeping an eye on the tach. Now, after the idle returns to normal idle rpm's, the presure will very gradually back off from the high end of the gauge to the low end of the "normal" range. (01 doesnt have numbered gauges) The tap,knock,ping,thudding...stays in step with the motor. After engine is at operating temp, it's still there just not quite as loud. I have done the following steps to try an eliminate this:
A. Changed Plugs
B. Changed Air Filter
C. Cleaned Throttle Body, I.A.C., etc...
D. Ran an engine flush and changed the oil again.
E. Ran Seafoam in Crankcase *1/4 bottle*, Gas Tank *1/4 bottle* and ran some through the Throtte Body into the intake *used half bottle* as described on the can (didnt use the vaccum hose on the brakebooster...let it go in directly through the butterfly plate on the TB.)
I looked through the TB as so many have said to do with a flashlight. No oil pooling, in fact it was clean as a whistle. (did this before using the Seafoam gimmick, and before i cleaned the TB the first time)
This thing is driving me NUTS!!! I'm concerned because I love this truck...and I am worried that one day its gunna go BOOM and launch a piston into low orbit. Can you guys help out an old retired military fart and maybe give me some diagnostic "steps" to locate and tackle this issue?
I dont have a stethescope, and I have done the "stick your finger on the injectors" trick. The Injectors are probably the quietest parts on that engine.
P.S. No codes: "done the key on/off thing too"
Any and all "Constructive Advice" please!!!