The motor in my truck has a miss and a constant tapping noise. What is the most likely problem, and fix?

Question

The motor misses, with the tap, but otherwise starts and runs smooth. Until it warms up. Once the engine is warm or hot, it begans to pop, and have a detonation knock, which actually sounds like timing, but I am not sure what that has to do with the tapping noise and the miss.

Answer 1

Yep. Sounds like you got a bum lifter. It may be dirty, or it could be collapsed. If it's just cruddy you can clean it with additive, but a collapsed one needs to be changed. On the other hand, you could have a bad rocker arm. Or a broken valve return spring. Or a slightly bent pushrod. Or you bent a valve stem. Too many things it could be without more info.

Most of it is in the top end, the head(s). So if you are handy with tools you could probably fix it yourself. Pullin' the valve cover (After getting a valve cover gasket) on the offending side if it's a V 6 or 8 could get you a good enough look at the valvetrain to make a diagnosis on the spot.

Answer 2

you need to put year/make/model and engine size.

so as a guess:
the tap could be a stuck valve, it's probably hydraulic, otherwise, you'd hear a lot of tapping. the auto parts stores sells a product called Lifter Free or Valve Clean, something to that affect. all it is an oil additive with a high amount of detergents. in about 40 miles the tapping should be quieted, if it is plugged up.
you could have the wrong spark plugs in the motor, and you're right, it sounds more like the timing is off.

In all out honestly, an oil change, and a tune up would do wonders for you at this point, because it starting to sound like the engine is going that
route.

Answer 3

Check the timing and the plugs, sounds like something is predetonating.

Answer 4

Bad lifter.
New lifter.