to all, i have a 97 chevy cavalier 2.2l ohv that's running so-so, i have a code p0300 that won't go away. i have replaced in the last year and a half the following, TPS, MAP, EGR. PCV, SPARK PLUG WIRES AND PLUGS, BOTH IGNITION COILS, IAC (TWICE), FUEL FILTER, ALL INJECTORS and CPS. the car now seems to run against a strong wind when i'm on the highway at about 65 mph bucks and at times the cars shakes a bit due to i guess engine misfire? any help would be appreciated

Have you done a compression test?

thanks for the reply, yes i did have it done and they told me that for the age of the car, the compression reading were within parameters, they said that the bleed off was acceptable no problems fore seen? i suspect that it might be the spark plug wiring or worst, the coils? thanks again for the response

How about changing youre O rings on youre fuel injectors.

unless the o-rings on the new injectors that were put in were bad to begin with, they should be alright cuz i had them replaced about 18 months ago? but like with everything, anything is possible? now get this, as of last night the dang check engine light went away, some gremlin might be at work here? lol!!! thanks to all for the inputs/suggestions, i guess i'll be here again if the CE comes back again with a P0300. p.s. the engine is running smooth, go figure lol!! HAPPY HOLIDAYS TO ALL

Check your fuel pressure the next time the code comes back. I bet your pump is on it's last leg.
Also check your fuel pressure regulator. It's vacuum controlled. Take off the vacuum line and if fuel comes out, then it's not good.

thanks, i'll do a fuel pressure check, i just have to figure out where i'm going to tee off and put a gage? i bought a fuel regulator about the time i started experiencing this code, maybe i'll just install it for GP? lol!! thanks again for all the comments/suggestions