I have a 91 special edition miata and when I give it gas in any gear it is very slow and does not want to accelerate. In 2nd gear floored it will not go past 5000 rpm and will definately not redline. Yesterday on the highway it would not do more than 60 in 4th gear. I know this is not a clutch slippage problem because the tach will not race up fast. The car idles and runs fine it just has no go. Any suggestions or possibles fixes?

 

Three most common causes of power loss as you describe are badly restricted exhaust, timing belt having jumped a tooth or two, and low fuel pressure. Does the engine rev up to redline very quickly in neutral?

 

special edition means supercharged right? if i were you, i would check all of the seals behind the supercharger for leaks. the thing here is that, if the supercharger boosts, the MAF sensor, which is right behind the airbox, senses the air flow and pumps enough gas to handle the air into the cylinder. if there is a leak behind the supercharger, the air won't make it all the way to the intake but the fuel will and it will overfuel.

i would also explore the timing belt as the supercharger issue is kind of a long shot but a shot none the less, but if your car is firing up without starter fluid, i don't think it would be low fuel pressure.

 

Well, you have a 90 Miata? correct? It might be a problem with the Short noise crank. The key way on the crant to pulley wears out the crank. Let me know if you need more information.