I just bought a 99 4runner about two weeks ago (specs in my sig). The first weekend I had it, I took it out to the desert to do a little wheeling and had a blast. Headed back home on the highway though, I notice that if I step on the gas, the truck pulls hard to the left, and if I abruptly let off the gas, it pulls hard to the right. I might have the right and left switched up, but it pulls the opposite way for accel and decel, I know that much.

After doing some research, it looks like this could be multiple things. I'm replacing the LBJs this coming weekend anyway, but I saw one where it was the rear control arm bushing that was causing the problem? And I've heard others that say it was due to their brakes, or tires needed rotating; but in my case, it was ok on the way to go wheeling, and not ok on the way back, which makes me doubt that it's the brakes or tires.

Any other possible culprits, and has anyone else experienced this? It's most noticeable at highway speeds, but it's still vaguely there at lower speeds as well.

Thanks!

Check your upper and lower rear control arms. If i had to guess, i would say you broke an upper.

Sounds like it would be something to do with rear arms... Maybe bad bushings on the lowers

Thanks for the suggestions! I'm definitely going to add the upper and lower rear control arms to my list of things to check out when I pull the 4runner into the garage tonight.

Well, both the rear upper and lower control control arms seem to be just fine. There is a little play in the right rear stabilizer bar link, but that's about it.

Any other ideas?

some of the brake caliper pistons are seized. Look first on the side where it pulls during braking.
if confirmed that the pistons are seized, consider doing the tundra brake upgrade.

I'll have to check this for sure tomorrow, but I'm fairly positive it doesn't pull under braking. It tracks straight during braking, and it tracks straight as long as you don't step on the accelerator too hard, or let off the accelerator too quick. It almost feels like torque steer, I guess that would be the best way to describe it.

Could it still be the pistons seized if it only does it under acceleration or letting off the gas abruptly, and not under braking?

Sorry, i misunderstood your statement on deceleration, thinking that you were braking. I had experienced seized pistons before and i didn't notice any pull during acceleration/deceleration.

just a crazy thought, could it be that you don't know that 4WD is engaged due to a busted solenoid switch up front or on the transfer case and also a busted CV on one side.

Check your front lower control arm bushings. I had the same problem, and I replaced them and it got rid of my pulling completely.

I have no ideas to add but, I would like see some pics of your runner.

I engaged and disengaged 4wd just to make sure I was really in 2wd and everything checked out.

They seem fine, but I might add that to my list of things to do anyway. I contacted the previous owner, just to see what his thoughts were on it, and he said it was normal for him, so I'm not going to worry about it too much now. Thanks for all the suggestions to everyone, I appreciate it!

You bring up a good point, I need to get some pictures of this thing. Lol I'll see what I can do.

Just a small update. I replaced the LBJ's, and I'm not sure if it's just my imagination, but it seems to have helped some with the pulling problem. It's still there, but doesn't seem as bad now. I also contacted the previous owner to see what his thoughts are, and he said that's been normal ever since he lifted it, so I'm not too worried about it now.

And here are a couple pictures for those who wanted to see the 4runner:




Thanks again to everyone that had suggestions.

Any chance you ever figured this issue out @Kraze ? Its not very fun when you are driving on steep snowy roads and your car starts pulling one way or the other.

Nope, still haven't figured it out. And now I don't have any sway bars so it's even more noticeable haha. I am probably doing the front LCA bushings soon though, so I'll have to see if that helps at all.

Look for my thread on the lower control arms. You can buy complete replacements for only a couple dollars more than the cost of the bushings.

I purchased the uppers brand new. And only found out the lowered also came as a complete assembly after I got done pounding in the bushing inserts.......and was doing research on documentation for my thread.

I still say you need to replace them.