Violent engine shake and really rough idle

Well there may be other issues but also sounds like your motor mounts are bad. May also be misfiring for many possible reasons like plugs & plug wires, fuel injectors dirty or bad, if your check engine light is on have the codes read.

Yeah the check engine light is on. It ran just fine for a long time then I replaced the battery and now it runs lime this. But I will get the codes checked thanks.

After codes are read, read up on all possible causes for that/those codes to appear before buying parts as it is likely combined reasons for a certain sensor to send information to computer and then code(s) set. Basically that sensor is not always bad. Its receiving in-accurate information connected to its primary function.

What could it be my ford explorer it shakes really bad & when i push the gas it won't go

I have this issue, sort of. 99 sport 2wd, 4.0 pushrod. Intermittent. Sometimes it's great, sometimes you think the engine is going to part company with the mounts. Best description is a death rattle, like a loose front end on my 1950 F-1. Fuel filter early this year, 6600 Mac's injector cleaner (every time), Autolites, Belden wires, single 6 port coil pack, air filter, cleaned MAF, had a mouse eaten wire to #4 injector, unable any more to do that myself, had it done, no change, shop changed the injector (their scope showed an occasional #4 misfire), no change. I did EGR test, normal. NO CODES except the P0401 for the road test with EGR unplugged to see if it was dumping too fast...no change. Did NOT light CEL. Transmission shop drove it with me, said not trans as tach did not even flutter when this happened....he said trains issue would have caused tach to flutter or move radically. DeOxIt5 cleaned engine gang plug, PCM gang plug, performed wiggle test on all wire bundles and plugs while running, no change. Fuel pressure at 60PSI, loaded st 2200 RPM, still 60PSI. Serviced trans....no change. Can start at 25, usually goes away at 40, but shop said still there at freeway speeds. Plugs on LH bank look normal. No oil, no burning, no pearly white. Thought PCM, but all the folks I know who do this or did say 99, no. Never the PCM. Plug voltage about 10K at each end, cylinder balance normal. Haven't done compression test yet (have to wait for pain levels to go down). Shop threw their hands up (they said exactly that), 35 years of wrenching and I am at a loss. Has to be simple. Thanks.