NEED help please
 

Ok so I have a 2001 protege es 2.0, with 166xxx. Has VERY poor hesitation, has better pick up when I'm not trying to floor it, but when it I try to floor it, it goes no where. Also all of my lights are dim and flicker until I hit 3500 rpm then everything gets twice as bright. Battery light came on and off 6 time in a matter of fifteen minutes. It keeps getting the notorious random misfire code

Things I have done:
New plugs, wires, coils
New egr valve, intake gasket, valve cover gasket
New mass air flow, cleaned throlled body
Had both battery and altenator tested, both are good
Cleaned the top end of my motor and a few other things I can't think of at the moment but no matter what i do to fix the problem its not working.

Ive heard it could an electrical problem where I'm not getting the right amount of voltage throughout my car due to a bad ground or something.

If anyone can help I'd greatly appreciate it.

if the voltage is low, you will get misfires. check for battery connections, and alternator connections, alternator belt tension, and good ground. if you can recharge the battery or swap it with a good one from another car, do it. if conditions improve, you know you have an electrical issue. if you start the car and disconnect one battery terminal and the car dies, you might have a bad alternator. i would double check that alternator. it sounds to me like a bad alternator.

Couldn't have said it better myself. My first thoughts: Alternator on a 13 year old car. Grounds should also be cleaned. Running an extra ground wire from the engine block to the negative battery terminal is always a good idea, as well as another car body ground.

agree with the extra ground wire idea. a quick check for good ground is to get a booster cable and connect it to the battery negative post and the other end to a good metal place of the engine block. fast and easy. that will tell you if you have a bad ground connection to the engine block. you can do the same, but connect to the car chassis to check for bad chassis ground. keep us posted. check that alternator belt tension, and condition of the battery cables. they might be all corroded inside, under the insulation.

Ok cool thanks ill try all these ideas tonight when I get home and will let you guys know.

Ok so i was checking and whoever had the car before me spray painted the whole engine bay encluding wires and ect., but now when I start my car my o/d flashes and when I hit the gas all my lights get brighter and my radio cuts out, where would my ground wires be?

that is one specific question i cant answer. do what noggin suggested: run a wire from the bat neg terminal to a spot on the engine block. and one to the car chassis. is things get better, you are done. if not, check the alternator. if you have a volt meter, connect it to the battery terminals, start the car and get the revs to 2500-3000 rpm and read the voltage. it should be 13.5-15.1 volts. turn on the headlights and the voltage should stay the same. if not, replace the voltage regulator or the alternator. again, make sure the battery is good and you have good grounds. but i suspect that alternator.

Ok so Im still having problems, gotta get wire to run a new ground to the chassis and block, but I started it up this morning hoping it would run differently(in a better way) and still nothing. I noticed I have that loud noise that belts make when there going bad but the belts are brand new so I'm thinking its my alt pulley, could that be the cause of all of my problems? Plus I noticed I'm missing a in the wire harness that goes to my fuse box under my hood. Where would my major grounds be exactly on a protege? I can't seem to find them anywhere.I also swapped my battery with my friends and I did noticed a brightness change in my lighting, so could that mean I have a bad battery too even tho both were tested good?

If you have a bad alternator, your battery will also be affected, since the alternator isn't putting what it should. Your alternator is having a hard time putting anything out due to the seizing of the pulley.
Don't know where grounds are. I just installed 1 to the engine as i don't even know if there is one (may just go thru the bolt mounts). As far as the body ground is concerned you should be able to follow it from battery. It may go to starter as well.
Alternator change time!

deal with the alternator first, then lets see about the battery.