car won't go over 35 mph.

not sure ck fuel filter for blockage to start with or poss plug exhaust system

It could be...it could also be a fuel problem, timing problem, exhaust problem or even a brake problem.

Could be a problem...................to vague a description on symptoms to narrow down causes. need to have it looked at/test driven by your local garage. my guess after others are checked , would be exhaust restriction. How many miles ? What overall condition? What recent repairs or maint.? Where is the spare tire for a unicycle kept????