Can you change a piston with out pulling the motor.

have mechanic run compression test. might need rings or valve job

Hey 94 TOY...

When did the problem start? Before you changed the wires and plugs? Or did it start, AFTER you changed the wires and plugs? Did the problem remain the same BEFORE & AFTER you made the changes?

1 - If the TOY ran fair to Okay before you did the work, then you may have done something wrong when you made the cahages. Check for correct plugs and firing order. Check for cross wiring. With engine runing pull one plug wire off each plug one at a time. Each pulled plug wire will slow down the engine. When you pull a plug wire that doesn't react and does not make any change ON or OFF that cylinder Plug.
Then that cylinder is not firing.

2 - Check for spark at that wire. If you do-not have Spark there, But the other wires do... the wire going to that cylinder is BAD.

3 - If you have the correct firing order and spark at all cylinders then the cylinder that did-not change the speed of engine has a compresstion problem. Bad valves, Piston or rings are bad... Major engine work and Major repair bill for the repair job.... GOOD LUCK....

either blown head gasket or cracked head, coolant only escapes into motor in two ways, before you replace head gasket again, pull head, have it magnafluxed ( To Show Cracks) if there arenonehave the head resurfaced

You will have to change the cylinder piston; the ring around the piston is what causing this to misfire. As you can see, every time you remove that one spark plug, to look as liquid is been spill on it. The ring around the piston is damage and the cylinder is not burning the oil and gas as the spark plug send fire into the cylinder. contact your local mechanic for hands on help.

im assuming you mean piston rings. to change your piston rings you need to remove spark plugs, empty your oil, remove your oil pan. unbolt your crank shaft and anything attached to it. at this point you should be able to pull your pistons down remove the rings and put new ones on as per the instructions provided with the new rings. use a hone or at least acid wash the cylinders before you reinstall your pistons. also make sure you reset your timing correctly. goodluck

possible causes of oil fouled spark plugs include bad/worn valve stem seals, worn or scratched cylinder walls, broken /leaking piston rings

Are you replacing the belt because it broke, or just routine maintenance? If you replaced it because it broke, you probably have bent valves. When a belt breaks, the cam(s) stops turning, but the pistons keep going up and down a few times before the engine stops completely. The pistons will hit the valves that were open at the time the belt broke and bend them. If this is the case, the heads must be pulled off and repaired.

Replace the spark plugs and plug wires.

If you have no compression,You either have a bent valve,or a Hole in the piston.Or both.

You will need to take out the spark plug in #1 cylender standing in front of the truck looking at the motor it will be the first spark plug to your left. shine a flash light down in there and see if you can see the piston if it is at top dead center. or all the way to the top. then pull your distributor cap off on look at the rotor bug it will be pointing at position # 1 ( you can tap the key over to get the piston all the way to the top.) having a friend do this is helpful. now to get to the firing order on the cap it is 1,4,2,5,3,6, clock wise . 4.0 liter and all V6 motors the cylinder arragment is
3 6
2 5
1 4 standing in the front looking at motor