My strange MR2

I have been driving this Toyota MR2 1986 since 6 months: when I start the car it steam very well. The problem begin if i try to move forward or backward: the engine stop immediatly if I do not keep my foot on the accelerator! So, at any stop either I engage on parking(and the engine would not stop), either I press the brake with half pressure on the accelerator pedal. The spark plugs, filter, injectors have been changed but the same result!Any idea on what’s going on?

By ‘steam very well’, I’m guessing a puff of white smoke out of the tail pipe? Or was that a typo, and you mean ‘seems very well’. Please clarify.

Also, given the age of the car, a compression check would be a good start. If the compression is low, this engine is worn out. A rebuild would be required. How much oil is consumed between oil changes? This is another indicator of excessive wear.

If you are observing steam coming from anywhere on the car, then there are some very serious problems with the engine or the cooling system. Please clarify this “steam issue” for us.

By steaming I just want to say that the car’s accelaration is very normal,as long as you keep the car on parking. There is no smoke coming out of the tail pipe(It happenned once and that was when I bought the car: the air filter was changed and I have never saw the smoke again)
I have been driving it for 6 months but not every day(I use it like 10 to 12 days per month) and the oil level is good(I always check it before I starts the car). I changed the oil, oil filter and spark plugs a week ago.