What causes tapping valves? - 1994 Plymouth Acclaim

Some tapping is normal with age and mileage. Wear on the cam and lifters and followers causes it.

Most engines now use hydraulic lifters and they can leak a little, this causes space between then lifter and the push rod. This results in a tapping noise that goes away when they get warm or fill back up.

tapping noise is usually a problem in the head [valve train ] check oil level and oil pressure -tapping usually from oil starved ,worn or damaged -valve,rocker,push rod--also can check belt pulleys or alternator they can also cause a noise but the head area is the most common

Hi if the tapping is in top it could be valve adjustment. Otherwise it is the cam chain this is adjusted automatically so if its noisy you will need 2 chains and 2 tensioners along wit the guid rails. This will be expensive unfortunatly. So check the valves first. Fingers crossed they are causing it. Regards Jim...

out of timing piston might need to machined

Bent valves would be number one cause. Check the timing. If you lost time, your valves are tapping the pistons causing the knock. When the valves tap the pistons they bend and don't close all the way, so the cylinders cant make compression.

It sounds like you have a valve tapping because when it warms up the valve expands from warming up so it will get quieter.

Hi, when you say tapping--you mean the cylinder is making a tapping noise? If yes, that is a bad lifter/lash adjuster that is not allowing the valve to open fully. This will cause a misfire, but even if it didn't, it would soon wear out the can lobe and then require a major repair.
If it's not tapping, please see my tip at http://www.fixya.com/cars/r6715318-causes_gasoline_engine_misfires . These are generic instructions. If you get stuck or need specific instructions for your car, please get back to me.

Yes i agree this is a egr problem can you put vacuum to the egr valve while it is running to see if the idle drops if it does then the valve itself is good .Then check the dpfe evr solenoids :)