Hi everyone,
Back with another issue with my 93 Civic I hope someone can help with. For the past month I have been trying to solve a problem with the engine shaking. It occurs randomly while at idle. The engine never dies out but it is shaking the whole car. I have uploaded a video to YouTube of the shaking. In the video it doesn't look like much shaking but it is abnormal.
Another detail I have notice is that sometimes at idle it will go from 6-700 RPM to suddenly go below 500. This is usually when the shaking becomes more obvious.

I have also noticed the tach will jump when I am coasting or braking around 1000 RPM. I have also uploaded a video of that too.

So far I have replaced the plugs, wires, distributor cap, rotor, MAP sensor, fuel filter, checked for vacuum leaks with the spray water test, tested the intake manifold gasket for vacuum leaks, and tested for a bad head gasket. I have also cleaned the IACV and the throttle body. I have ordered a replacement IACV but have yet to receive it.

Before I give up and take it into my mechanic, does anyone else have any ideas what could be my issue here? I did swap the fuel pump about 8-9 years ago. That may sound like a long time but that was around 150K miles. The Civic now has 180K miles.

Thanks in advance for any advice! Cheers!

 

1st vid could indicate bad/worn mounts.

2nd vid just looks like the transmission performing coasting downshifts, which is normal.

 

Forgot to mention all mounts have been replaced. Thanks for responding.

 

My 95 LX steering wheel shakes like that, although the rest of the car just barely shakes. 155k on mine.
Seems like the main motor mount (front left upper) is the culprit.

Mine only does it when it's starting to warm up/at temp, and the interior blower is off. When I have my blower going even at 1 and the recirculation option on (car symbol that is orange, shows arrows in rotation circle inside car) it doesn't seem as bad. Is your coolant topped off?

Your tach/transmission seem to work like it should. Is this something that just started (the jumping) or has it happened for a while and you are looking as to why?

 

We have decided to fix this Civic instead of purchasing a newer car. It is primary used to get me to work 15 minutes away. We got it for free in 2003 but it needed the trans rebuilt so we did that at 150K. Other then the trans we haven't had to do much to it until this year the suspension needed to be replaced. I replaced 95% of the suspension. IT also needed a new rack and pinion so that was done about a month ago. We are just trying to get it to run as best as it can so we can enjoy it, hopefully, for another 10 years.

When I did the head gasket test today using a block tester I did notice the radiator was not to the top of the cap.

 

Bleed the cooling system:

https://honda-tech.com/honda-civic-d.../#post38664177

 

I'm starting to wonder if I have a grounding issue. I'm now noticing when I turn on the lights, heat, or when press the window buttonn the idle will change and draw more power from the statem.