Contour Enthusiasts Group Archives Forums General Troubleshooting vibration?

A bad fuel pump would show signs of failure when the demand for fuel is the greatest (ie. hard acceleration or ascending a hill) or when there is very little fuel in the tank. Doesn't sound like it to me.

If you have not done any injector maintenance yet, you should try a bottle of injector cleaner in the fuel tank. I like Red Line SI-1. A chemical decarbon might not hurt either.

But the fact that it started happening after changing the plugs may still be significant. Sometimes ignition misfires manifest themselves in strange ways, even with RPM specific or light load misses. Did you look at the plugs again? Did you crack one when installing it (this sort of miss can be from a cracked plug)? Did any of the plugs pick up any strange deposits? Did you try substituting a know good coil?

Lastly, it could be an out of balance problem. The first harmonic for a vibration to show up from something out of balance is 1700 RPM. What accessory on the engine it turning at 1700 RPM when the engine is at 2300 to 2500 RPM? Alternator, power steering pump, air conditioning compressor, water pump? Running the engine briefly with the belt off would confirm all but the water pump.

i've already tried the injector cleaner and pulled the plugs again to check for gap but didnt notice any crack. Is there any specific place i should look for a crack?

The outer porcelin. The portion that is outside the engine, above the threads. It is often at an angle.

would a coil pack from a 96 taurus duratec be a good tester to see if mine is ok. If by chance it is a harmonic balance on my shaft how hard is it to change and how much are the parts?

The 96 coil should be the same.

I'm not talking about a shaft out of balance. I'm suggesting it may be something like the alternator. If you can dteremine which accessory is causing it, replace that accessory (alternator, power steering pump, air conditioning compressor or compressor clutch). Confirm that the problem goes away with the belt removed first.

Thanks i'll repost again when i get a chance to work on it this weekend.