need help quick!
 

I have a 1998 Ford ranger xlt 3.0 2wd with 180,xxx miles on it. My truck started shaking really bad one day and hasn't stopped unless I give it gas which then it has no power or I disconnect my battery and reconnect it then it'll drive fine the first time I start then if I shut it off and turn it back on she shakes again and has No power. The shaking occurs when I'm in idle or I'm keeping a constant speed. I have done a compression test and it was great. All the cylinders get good spark. The fuel pressure was low so I changed the pump now it's fine. I have a check engine light on and it's for an o2 sensor and a misfire that jumps around from 3 to 5 to 4 to 1 in No order. It loses water somewhere but not sure. Please help any info will be grateful.

Replace your said O2 sensor, also check vacumm lines.

I've replaced the o2 sensors maybe 1,000 miles ago.

Oh, I dunno then

Its losing water as in coolant? Does the exhaust come out white? Could be a bad head gasket. Your plugs are getting wet causing the misfire and the o2 is getting a bad reading from the extra moisture. The reason why unplugging the battery is working is because your resetting the computer. Now the computer is in "reading mode" trying to gather information rather then applying it. After its done reading now its going to apply what it thinks is right based off the information its gathered. If it was getting bad information from the o2, its going to start making wrong corrections.

The exhaust isn't white. Yes I meant coolant, and I replaced all the gaskets maybe 3,000 miles ago.