I use an AT212 Carina Ti 1999 Model. When the car is picking up there is a slight vibration which increases until 40KMPh and then wares off. There is a continous vibration when the car is stopped in Park mode and when it is not moving is drive mode? I have checked the timing belt, cleaned injectors , changed the air filters and completed a full tune up.

could be tires need balancing or front end alinement

Its more than likly a wheel speed sensor. they are mounted to your wheel hubs and they are analog signals.some even can get brocken by coming loose from there retaining brackets

It seems that the recommended plugs are NGK BKR6EP-13 as a first choice, but that the Champion EON 2 will also work. The NGK's are platinum tipped and rather pricey but needed for the high engine running temperatures.

have the wheel bearings checked, or drive the car in an open area where you can do s turns, the noise will be more pronounced when the vehicle weight is aplied to that wheel

I just had the same issue with a 1999 2500HD and the vibration got worse above 50 mph. Problem was resolved with a new driveshaft. Old one (aluminum) was badly out of true and the problem didn't really occur until I had the U joints changed - then bent driveshaft vibration was noticeable. New driveshaft resolved issue.

your oil pump does that on purpose - more noticeable with a dented oilpan as pressure is slightly increased. nothing to do until it goes (if it goes) unless you want to throw parts at your car anyways.

mcdevito75 here, If the vibration smooths out when you step on the gas pedal even slightly or increases, then it is mechanically related., Causes could be, Vacumn leakes, the small narrow rubber / plastic hoses that control the emission sensors / devices, Wrong Octane fuel (gas), dirty gas filter or dirty gas itself, a worn engine mount. I would start off with the gas (fuel), at your local auto parts store, Sears, Strauss etc. I would pick up and put in the gas tank a can of dry gas or an associated product to get rid of any water in the gas (fuel) Or at least a can of fuel injector cleaner. The fuel injectors in your engine could be dirty also.

this is commonly caused by a worn clutch release bearing and or a worn crankshaft pilot bearing.

its the pump it may have a blockage of some sort

try by replacing plug wires and spark plugs, also add some fuel injector cleaner to fuel tank, i will recomend techron brand or si1 from red line but you can use almost any one