Feel jerk under seat area when stopped at light

[CamelotShadow]

Disturbing burps/ jerks which are not associated with noise when stopped at light.

Noticed as it happens the oil pressure guage moves slightly in sinc with it.

Used to have a sort of lumpiness at lights but that was differe t that was sort of a loppy idle
I have changed a cracked vac hose & connected a disconnected air inject valve but that hose is bad too so have to change that.

Not sure what to associate this sort of odd sporadic burb/ jerk & oddly felt under the seat
or perhaps is the exhaust pipes

I have scraped a severe driveway ramp a few times

Have had to have the pipes secured a bit after that as that too caused a similar strange vibration sort of thud. Thing is that was mainly at acceleration from a stop.

I will have to have the exhaust pipes checked
get new hangers & make sure all is secure

Just wondering what this could be a symptom of??????

Still have to change ign wires dis cap & rotors when they get here.
Wires really look old

Car has new radiator/thermo /rad cap as it was runining hot
now runs 90 /95 C

I added techron fuel concentrate to clean injectors & such as the car has been sitting a few years...
I am not sure if this started before that addition though.

Other than that car is smooth & responsive when driving.

Note:
Still trying to source high idle when started but thats been getting lower with use & vac fixes.
starts 1000 then as it warms it goes to 1200 to maybe 1500 then back to 900 1000 when warm in park
idles normal in drive about 650



Thanks