Why does my Car throws a lot of white smoke when I turn it on!

If you left the gas in the tank you may have a gallon of water in it ... Don't jump the gun and assume you may have a major problem if the car otherwise runs OK ...but do get the oil changed and if the tank is more than 1/2 full go get some additive for the fuel

If it were mine I would dump all the old gasoline out! Gasoline turns gummy and thick and will clog the internal parts like fuel pumps! It will also collect condensation ( water) so that is probably the white smoke! Now that is assuming that the head gasket is not leaking coolant into one of the pistons ! Check coolant level and keep checking it if it drops and you dont see an external leak at a hose or weeping at the waterpump you can bet you need a headgasket! Change it immediately before you ruin the engine! Ok, back to the scenario that its just water in the gas tank! Dump the gas, make sure it doesnt have any rust inside the tank! Yes gas tanks will rust if water is present! So check inside for RUST, it can cause havoc with fuel injectors and fuel pumps! Once you have a clean tank run Seafoam in the tank with a minimum of a half tank of gas or a full tank of gas! Now the seafoam may smoke till it burns off but once it mixes and if you still get smoke start ups Go Check the Coolant level, did it go down, yes? Then you need a headgasket! Thats another major project but you will know where your problem lies! If my answer helped Please click my Mark Helpful link ! Thank you good luck!

I OWN A 2002 MITSUBISHI ECLIPSE GS SPYDER AND IT WAS RUNNING VERY GOOD BEFORE I PUT LUCAS ENGINE TREATMENT IN THE CAR, NOW THE CAR WONT STAY ON WHEN I GIVE IT GAS, AND NOW THE CHECK ENGINE IS ON . W3HAT IS GOING ON, CAN ANYONE HELP ME?

That engine cleaner u put in is just doing its job lol. I know it doesn't seem like it is now, but it is. What happens to me everytime I use it in something that's older and never had it in it before, the engines always run horrible after but what it is, is that all the carbon and all the build up junk in the engine that the treatment has cleared out, is now clogging up some other things because the "junk" didn't find its way out the exhaust like it's supposed to do! Usually it's fuel filters and things like those that get clogged up, but I've found that when I use it, I always have a spark plug or coil pack that's misfiring and some of those miss so hard it triggers other engine lights and service warnings to go off. So take it to the nearest advance auto and have them put it on the computer if the engine light is on and they can tell u which cylinder it is missing and start from there with fixing that, then drive it and see what happens next and repeat until it's fixed. Hope that will help a little bit anyway.

During hot days water condensation builds up in your gas tank , if you do not run the car for a month or two or more the water builds up inside the gas tank. When you start the car a mixture of water & gas gets pulled thro~ into the cylinders. Thats burns off as steam , just leave the car running to clear out the gas tank. Then when it runs clear switch the engine off. Do not assume its a blown head gasket & start stripping the head off yet ! When its cooled check the expansion tank water level, if thats gone down then get a cooling system check kit and use that to confirm you have a head gasket leak. I used the foam cleaner additive and it does produce a lot of smoke because its burning off the carbon deposits on the cylinders & valves , that too produces a lot of smoke as its doing the clean up.