Posted: Jun 23 2008 at 3:21pm | IP Logged

The oil was clean and the misfire has been corrected with the new wires and plugs.  Or at least the service engine light has not come back on or flickered since I disconnected the battery.  Would bad motor mounts of U-joints cause it to only shake between 40 and 55 with around 2000 rpm.  That is the wierd part to me.  I have never had one shake like that at a specific speed and rpm.  If you are going faster than 40 to 55 at 2000rpm it doesn't do it and vice versa.

Posted: Jun 23 2008 at 5:43pm | IP Logged

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bmoore85

Good advice from Boomer!

You should also try moving the front tires to the rear and note if there is a differents.

I had tires that acted like you discribe.

The tires could be improperly balanced, damaged or out of round.

... I bought a set of tires at 4W Parts in Ft.Worth  and after four tries they were un able to balance the tires and the replacement tires was just as bad. I took my Frontier to another shop and they balanced the tires perfectly the first try. 4W Parts sold me defective tires that were 3.5 oz out of balance and would only replace them with other defective tires!

I ended up buying a good ones at Costco.