Hi Angel,
The vibration is most probably from bad U-joints of the propeller shaft. Check them for stiffness or wear.
As to the engine straining before upshifting, you have misfiring codes which should be any of the following:
P0300, P0301, P0302, P0303, P0304 or P1399.
When misfiring occurs and engine lacks power, the engine computer delays the upshifting.
Misfiring are usually due to bad spark plugs or related parts and/or insufficient fuel which could be due to clogged fuel filter, low fuel pressure. Get them checked.
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Thursday, July 29th, 2010 AT 11:46 AM