Engine shaking, Troubleshoot and possible diagnosis?

Good evening to all Tacoma drivers/owners!

I have an issue with my '06 4.0 Tacoma. When I first purchased the vehicle it ran perfectly fine. About a few months after driving it the engine would shake during acceleration and sometimes even when easing of the throttle. I noticed the RPM would drop below 1500 and that's when the shaking would start. Eventually it would stop if when I step on the throttle again but I've experienced this shaking from 30mph, to 40mph, and now even 50mph. It seems to be getting worse.

I would greatly appreciate any ideas on how fix this problem before it worsens.

 

Any check engine lights?

 

The maint reqd light pops up for about a minute then goes away.

I feel like it might be a trans issue but I'm unsure.

I'm getting it checked on Thursday.

 

Check your motor mounts.

 

Thanks everyone. I'll check the mounts. If anyone else has more ideas on what it could be that'd be great to get more input. Have a good day!

 

Does the problem only happen while driving, or also while idling? As in, can you rev the engine and feel it stumble at a certain RPM?

 

Just discovered it does shake also at idle but not at initial start up. But I was at the stop light without the A/C on and it was shaking just like when I'm coasting and the rpm drops. It only shakes if the truck is moving. If I ease off the throttle it drops under 1500 then shakes until I step on the pedal again.

 

How many miles does the engine have?

Also, you said it shakes at idle, and it only shakes if the truck is moving. I'm confused by this.

 

Apologies for the improper communication on my part. Trying to reply on a smartphone during a rushed moment doesn't help.

145k miles

Shook on idle @ the stop light yesterday. Does NOT shake during initial start up.

Here's a scenario I have every day. When I'm accelerating, regardless if I have a heavy load or not at about 30mph if I ease off the gas pedal, the truck will start shaking (happens when the rpm drops to 1500rpm or below). The shaking has occured so far at 30mph, 40mph, and 50mph.

 

First thing I can think of, is to check all of your vacuum hoses for cracking. They may or may not have some, which could also be a separate culprit. If not,there is a possibility t it won't be long until they do start cracking, due to the heat cycles and age.

Has your transmission's ATF ever been changed? If not, then it needs to be done, and Toyota has a flush service if you don't want to do that yourself. Should have actually been done closer to 100k. This is just PM stuff that i am mentioning. Good to do but not necessarily related to the issue.

Also, take a look at your carrier bearing. It is possible that it is worn out and causing vibes.

Lastly depending on the type of wheels you have, the wheel weights could have come off.

With what little information that has been listed, it is hard to give an a cute answer. At least you have some more things to check though.

 

When you ease off the gas pedal, normaly the FI switch to fuel cut and then will switch back to closed loop in iddle mode at 1400 rpm or close.

You dont have an AFR gauge? If yes, you would probably see a strange behavior of the AFR. It can be the symptoms for a lot of different things like: Injectors, fuel pump, pressure regulator, O2 sensor, throttle body actuator.

In the same period the motor start to shake, have work on/touch the truck?

 

So I took the truck to the shop. I had it diagnosed and it turned out to be that the tires needed to be rotated. They're not the standard radial tires but they're huge mud tires that came with the truck when I purchased it. The mechanic said it could've been the truck having so much traction that when easing off the pedal, the tires were already worn due to the weight haul each day. Guess that was it. Thanks for all your help everyone!