i need help guys!! whenever i try to accelerate, my car just starts to hesitate between 2k nd 3k rpm.. then i did an obd2 test and it shows ehis code..PO303.. it says i have a misfire on cylinder no. 3.. i already changed the EGR valve, TPS, fuel filter.. i got new spark plugs.. and o2 sensor.. but then it still hesitates! before i got this problem with my car, i switched to supreme unleaded gas or 91.. i used to put 89 in it.. could this be the cause?

i couldnt find any vaccum leaks either.. and i already put an injector cleaner and nothing happened..

Originally posted by repiDpi
i need help guys!! whenever i try to accelerate, my car just starts to hesitate between 2k nd 3k rpm.. then i did an obd2 test and it shows ehis code..PO303.. it says i have a misfire on cylinder no. 3.. i already changed the EGR valve, TPS, fuel filter.. i got new spark plugs.. and o2 sensor.. but then it still hesitates! before i got this problem with my car, i switched to supreme unleaded gas or 91.. i used to put 89 in it.. could this be the cause? i couldnt find any vaccum leaks either.. and i already put an injector cleaner and nothing happened..

Don't bother putting anything else in the gastank besides 89. Did you properly gap your new spark plugs? Stock range is .048 to .050. Check your spark plug wires at the coil and down into the head, make sure they're secure.

Start there, start simple, and get back to us.

all the plugs and all the connections on the coil pack are securely tight. the gap.. im using this kind of spark plug http://shop.oreillyauto.com/productdetail.aspx?MfrCode=BOS&MfrPartNumber=4501&PartType=960&PTSet=A

That link doesn't work.

You should be using a NGK BRK6E or BRK5E spark plug. Gapped to .050"

You do not need to run expensive Platinum spark plugs or anything. Just get the standard NGKs.

(I assume you are non-turbo because you are using low octane gas.)

i thought about getting ngk.. im only using that cause the previous owner had those plugs in the car.. and yes im non turbo..

Have you checked your coil or ignition wires?

coil and plug wires. Those are what you should have checked before messing with EGR and other things.

Originally posted by CODE4
coil and plug wires. Those are what you should have checked before messing with EGR and other things.

X2. I'm running Bosch Platinum 2s and I havent had any problems with mine on 89. But definately check the coil and wires.

i got my car fixed guys!! thanks for the help!