it's not a thirdgen ... but I figured it's probably generally about the same in most cars...

my friend's got an 86 MR2.. basically, it runs fine from idle up to redline, smooth accelleration.. but when you floor it quickly, it hesitates and bucks hard... I'm almost sure the ignition is fine, cause it's fine through the entire RPM range.. and when you gradually press the gas to the floor, it's fine also.. only when you punch it hard.. happens at any RPM and in any gear... including in neutral.

 

There are a couple of possibilities.

First, you can't assume the ignition is working as it should be. High throttle openings create more mixture in the cylinders, and higher compression pressures. This higher compression can actually blow out the spark from a plug, or prevent it's firing, and is why spark plug gap is so important. An ignition system that can develop adequate energy at lower cylinder pressures might not be able to deliver engough spark energy at higher pressures.

Second is the fuel delivery system itself. Mixtures at high throttle angles might be incorrect (and probably lean) regardless of the volume of air flowing (engine RPM). This is why fuel system maintenance is so important. A good fuel filter, pump, and correct adjustments are necessary to enable the system to deliver the correct fuel rate at any throttle angle. In addition, the stochiometric ratio at high throttle angles is usually best at about 12.5:1 instead of the customary 14.7:1 for normal cruising, so even more fuel flow is required.

Third, and finally, you say his person is a "friend"? How good of a "friend" is he/she? Friends don't let friends drive Mazdas - or at least those that are not true rotaries. Take his/her keys and wait until they are sane again....

 

I guess he can call that person a friend then since an MR2 is a

TOYOTA!!!!!!!

I guess it just shows how much you truly don't like foreign cars.

 

yeah last time i checked it was a toyota mr2!

anyway, it could be as simple as a dirty airfilter, at least that happens on my dirt bike..

 

Mine does it. Does it bad too. Mines carbeurated though, and the problem is the pump shot. not enough "acceleration enrichment". but thats just me.