I have a '96 f150, 2wd, 4spd w/4.9 engine. I was under the hood last night, changed the oil and did some other things and with the hood up, I started the engine and noticed the engine just rocks and rolls when the engine cranks and once it starts seems to run without much movement. So I stopped it, pulled the coil wire and had someone crank it while I watched from outside. The engine just flops around something terrible when it cranks. I have never had an engine move about so much as this one. Could I have a motor mount that has failed? Is this normal for the 4.9? Is there an easy way to test the motor mounts?
Thanks in advance.

 

How I test them is; put the hood up, set the parking brake, put in 1st, give some gas, let the clutch out a bit, if the left mount is bad, it should lift on that side. Do the same thing in reverse to check the right one, but those seldom outlast the left one.

 

how many miles?

 

The truck has 130K mile on it.

I tried Your method of checking the engine mount. The engine moves very little in 1st or Reverse so I'm assuming the Motor mounts are good. I seem to be getting a lot of chatter when I start to release the clutch. It a new clutch pressure plate, maybe 10K miles at the most on the new clutch assembly. I don't know if the two are related or if this might be a new problem. The clutch slave unit has also been replaced.

 

I was playing with my '87 4.9 today cleaning up the balancer to find the timing marks. I was spinning it with a hand held button connected to the relay. Anyhow, it rocks around quite a bit when on the starter too. I never noticed before. It usually starts the first time a piston gets near a spark plug, so I've probably never seen more than a turn or 2. I'm calling normal behavior on this one