weird vibrations...

[SpHiNxXx]

hi guys... you're probably already getting sick of me... but its just one thing after another!!!

so i "fixed" my AC problem which was burning my belts....
i fixed the alternator problem (had it rebuilt) that was making so much noise... i did a fresh oil change with mobil1 full synth... also added some seafoam and some lucas oil to the mix... everything when smoothly.... BUT now when im driving... and i slow to a stop theres a weird like vibration felt all over... its not a violent shake or anything but its noticable... could it be the Lucas Oil? or Seafoam?

 

[PobodY]

If you were using a fully synthetic oil, why did you also add the lucas oil and seafoam? - I'm not trying to attack you, but I thought the point of a high-quality oil was that you didn't need to put additives in it.
Is the viscosity right for you, I don't know that the oil pump working hard would cause vibrations like that, but it's an idea.

If the vibration is when you're slowing down, I've had another idea; is it your exhaust vibrating against the chassis? Or, what are your engine mounts like?

 

[SpHiNxXx]

yea i know full synthetic doesnt need any additives but i though it couldnt hurt.. and as for the seafoam i just wanted to blast out any remaining sludge and what not... i didnt use much... about half (if that) of the recommended amount... BUT i did notice the oil pressure gauge reading slightly lower than before the oil change... it reads to the first line.... at idle... and 4+ under load... it used to read 4 at idle and 6-8 under load. as for the exhaust idea... i do have an exhaust leak at the flex pipe... but i dont think thats its cause its not a metal on metal sound just a subtle rumbling....
engine mounts as far as i know are okay.. this all happened after i installed the new alt.... and new oil... im leaning towards the additives... maybe ill flush it out and try without addatives...