K here goes, i have recently had an ongoing odd problem where the engine would bump and bump hard, i took it to a shop and said find out whats wrong with my car, they came back and said the computer had taken on water, so i replaced it, No good did not fix the problem, i have since replaced or replaced before this happend
ALL ELECTRONIC PARTS ARE NOT AFTERMARKET they are genuine bosch.
New Distributer ( Came With Cap And Rotor )
ECU
ECT
IAC
Knock Sensor
New Fac wires
Harmonic Balancer
T Belt
Alt Belt
Water/Stearing Belt
Air Intake Hose
All Other Vac Hoses
New Flame Trap and Hoses
o2 Sensor
Switched Out Coil
Fuel Injectors Have Been cleaned
Engine Harness Inspected and In good condition
Preformed Air Mass Test seems to be okay


The Tach ( RPM gauage ) does follow this bump, when i go from Overdrive to 4th ( passing gear ) the problems shows itself till i restart the engine, since i have replaced the Distributer this has not happend, though while at idle tonight the engine bumped hard twice, after hitting the gad alittle all went back to normall, when i got home i switched out the Coil and ill see if it was that, but does anyone have any clue as to what i should be replacing next? at speeds of 70mph or more this problem had not showen itself only below 70 mph,
I also have a weird whitle like sound comming from the valve cover which you can only hear with the hood up and it happens between 1000 rpms and 1500 then go away any clue what this might be? it is deff comming from below the valve cover. Other then this problem the engine runs like it is brand new.
Thanks All