engine vibrations 1800-2800 r's

[jd96969]

New to Infiniti , Bought 1990 Q45 off of Ebay 260k mile . Ran great just had Ct. emissions done now I notice vibrations from engine. 1800-2800 rpm . none after ( down shift and it flies ) no irroneous smells. in park slowly raising r's vib starts in at 1800 and gone at 2800. is this enough to cause vibs while driving? Vibs bad during this range while driving. above this is ok. engine and exhaust dont sound smooth .

[Q45tech]

You would be surprised how well [functional] a Q engine does on 7 cylinders if you can stand the vibration.

How is idle can you feel the engine running with your hand on the plenum.

Worn out engine mounts let a lot of vibrations surface........as do low compression [worn rings]. Is the engine using any oil [at 263k] mine doesn't use a pint in 90 days or 3,000 miles.

When were transmission mounts last changed.

A 260k Q should be on its 3rd set of transmission and engine mounts now.

When ever you buy a 260k car you gota be ready for $5,000-$10,000 in rehabilitation.

[jd96969]

Pulled plugs all look good ( Grayish ) checked compression all cyl. 150-155 . Hit MAF with brake cleaner , BIG MISTAKE. car went into safe mode. Used a product i use in my industry called rubber rejuvenator and cleaner by sprayway in cal. Yahoo back to a running car.. Picked up tec. and put into tank within 20 min vibs minimized.. I'm back on track. engine mounts good transmission mounts good to fair.. thanks for the assist.. Jd