Hi I am working on a 93 Mazda 323 1.6L 5 speed. It seen to miss fire at idle sometimes trigering the check engine light. And some time il be doing 100km/h and it miss fires sometimes the light will just flash but other times it will stay on till I restart the car. Today it had this miss fire that was odd. If I left it at idle it would die but if i revved it up it would run rough till it gout around 4000RPM then it would seem to run fine. So I parked the car for 2 min Got a coffee started it up and she ran ok. Dose any one have any clue? It has a new timing belt, new plugs, weirs cap and rotor from last march and it was parked this summer. But it did that before it was parked and before timing belt was changed. That is whey I changed it any ideas??

 

i assume it notting to do with your belt .. maybe ur gear ratio is in bad shape ..i would recommend u to try to check it out .. ..if not maybe rpm droping is due to engine power .... check ur engine too .

 

You have a bad oxygen sensor, most likely, or you need a tune up, or, you have a bad vacuum leak.