I have a 99 EX that I've been trying to diagnose multiple shakes and vibrations. Hopefully the collective brain can help me get to the bottom of them.
1. While driving on the freeway, there is a vibration that starts around 67 mph and goes away at around 70. No braking or anything and it happens whether I'm accelerating through that band or cruising around it.
2. The steering wheel shakes at 80 mph. Not terribly, but enough to be an annoyance.
3. When braking from freeway speed (65+) the entire van shakes from about 50 down to 40 mph, like when slowing on an off ramp. This is my biggest issue. It doesn't happen when braking below 65 and it does stop shaking if I lift off the brakes. It seems like a rear brake issue as I replaced the front pads and rotors as well as the rear shoes and it still occurs. I'm assuming I need to replace the drums, I'd just like to confirm that this is a likely fix as I'm getting tired of throwing parts at it. The rear shoes still had plenty of life when I replaced them.
4. The tranny clunks when going into reverse when cold. the weird thing is that it clunks again as I'm backing up as if something else is engaging. The second clunk only happens once and it's usually within 20 feet or so after I start moving. There is also some delayed shifting when it's cold and moving at slow speeds between 1-2 and 2-3. Van has 106K, I've had it since 77K and I dont know if the tranny's ever been fixed/swapped/rebuilt, or if this is even the chronic issue with these trannies. I almost suspect a mount somewhere.
I did change fluid after towing a boat for 600 miles last year. The issue was present before towing and, while the fluid was brownish when I changed it, changing the fluid had little effect on the issue.
5. I have the PO402 code like everyone else. it comes and goes on it's own (I got tired of clearing it). I'm not going to replace the cat as it doesn't sound like the real fix. Is the general consensus the rear 02 sensor? I've done the EGR cleaning I found on this site as well as trying premium fuel and injector cleaner I saw here as well. The EGR helped in other areas and the premuim/injector cleaner helped long enough to get through emissions testing.
I am getting the tires remounted and balanced today as a first step. I've considered replacing rear drums, shocks, struts, mounts, etc. but I don't want to just start throwing parts at it without knowing it might actually fix my issues.
