Hard shaking/vibration

I have a 2001 sr5 4wd. Suddenly experiencing shaking Upon starting/idling. Can see engine shimmying back and forth but shaking feels harder than it seems engine is moving. Can feel it in seat, steering wheel. When I put into gear it gets worse. Any ideas? I thought engine or transmission mounts but they seem fine. Changed MAF, no change in function. Spark plug? Piston? I have no idea. Anyone have anything to suggest?

 

Try a compression test. See if you have a dead cylinder.

 

A bad injector may do that too. You should be getting a misfire code. Did scan for codes? Is the CEL on?

Pull all your spark plugs and inspect them for anything odd to narrow it down.

 

i did have a po171 code and that why I changed the MAF…haven’t changed 02s. I picked it Up from someone a few months ago who claimed he changed the plugs. How would I check the injectors?

 

Pull the plugs. Verify they are the correct Denso plugs. Check to see if they show signs of fouling. So many people don't buy the correct plugs.

If you find fouling, record which cylinder and go from there. Like was mentioned, a wet and dry leak down test is good to do and is going to tell you if the rings or valves are shot.

You can't tell which injector until you figure out which cylinder is an issue...or until you get a specific code.

 

My rig has, every so often, like once or twice a year, a noticeable minor vibration on cold start up. It goes away after a minute or two. It's been doing it for 15 years. Over the years, I've replaced many things and I think it's probably just a goofy injector. Never threw a code.

I was trying to think about a SEVERE engine vibration with no code and all I can think of would be something like a bad harmonic balancer. or a bad Torque Converter?

What happens when you put the car in NEUTRAL? And then rev it a bit?

 

the vibration is less in neutral but still noticeable. No nearly as bad as when it’s in gear or parked tho.