switched engine in my 95 mazda protege does not have any acceleration.

Question

will not exceed 60 m.p.h. full throttle. have changed o2 sensors and tested all other sensors. what am i over looking i'm at a dead end

Answer 1

The best test tool to diagnose this condition is a vacuum gauge, the use of a vacuum gauge will help determine if the exhaust is plugged , the timing belt is off  a tooth , or the timing is off.

 A engine that is well balanced will have a vacuum from 18 hg to 20 hg.  At park or neutral hold the acceleration down the needle will go to 0 while hold the acceleration the needle will go to 18 to 20 hg. if the exhaust is plugged the needle will creep to 0.  If the timing is off whether its from the distributor or timing belt the vacuum would be less that 18 to 20 hg , about 15 hg would indicate a timing problem.

 Here a vacuum gauge found this problem , this vehicle would not accelerate pass 40 mph. but idle great .its vacuum at idle was 15 hg, timing was good by use of a timing light, Further inpection lead  to check the timing alignement mark which was off a tooth.