I've got a goofy 1994 4 runner v6 4wd auto with 230k on body and 50k on engine. The previous mechanics were pretty bad, put the driveshaft in backwards which has done god knows what to my poor transmission. I need to change the rear u-joint, but that's not the problem since it vibrates even in park.

While in park, it idles rough causing a vibration that feels like it's coming from transmission. With a buddy standing outside feeling the engine, there was less vibration in drive then while in park. I've gone from Park to L and it only vibrates in park and neutral. While in drive, it also gives a vibration while giving power to the wheels, and sometimes the vibration doesn't kick out even after I've let off the gas, seems to wait till the rpm drops, then trans does it's thing and it's smooth again. While in drive with the brake pressed at a light, no vibration, but as soon as I accelerate, there it goes again. The vehicle doesn't want to pass emissions due to an egr system problem I can't figure out, maybe the egr intake tube is clogged or the vaccuum lines out of place.

Any ideas? Last time you guys were right on the money.

 

More info- I now suspect the engine. In park and neutral it idles at 1000 rpm and sounds pretty bad, when in drive or reverse, 750rpm and sounds pretty normal. The worst is when around 2000rpm in drive it gets a really bad rumble and vibration. While on the highway though it sounds normal going around 70.
Does that help at all? I'm at a loss since there are so many things that appear iffy on this old truck.

 

If you have an EGR Problem that would do it, did you try blocking it off just to test? Are you getting a CEL?

 

yeah, I tested bypassing the entire egr system and it runs same. Haven't looked for cel codes. Replaced spark plug wires after I saw they were completely corroded, at least one cylinder wasn't getting spark the entire time I owned it. It now runs good, but vibration coming from transmission is still present in park, neutral, and in 1st, 2nd gear for lower rpms.

I took it to a transmission shop (for free) and they said that the transmission was in good shape, all they did was throw it on a lift and run it through all the gears. They also told me it was probably the lower balljoints or the steering shock which makes absolutely no sense at all. It makes a horrible sound when I make sharp turns which is what I suspect they were trying to fix without even noticing the rumble from the transmission though I told them about it. any ideas?