1999 Chevy Blazer S10

[Bonnie]

how do i fix diagnostic code p0300

[Terry]

Code P0300 is a misfire code. There can be many causes for this to turn on the check engine light.
1. A bad spark plug or plug wire
2. Vacuum leak if the misfire is at idle.
3. Stuck fuel injector.
4. Internal engine mechanical problem.
5. Engine running lean or rich.

Most of the time a P0300 on a Chevy Blazer is an ignition problem like a spark plug, plug wire or distributor cap and rotor. Also the fuel injector tend to get clogged.

[james]

The more I push throttle while driving the more it hesitates, but if I barley push the throttle it will run on all 6 cylinders.. But the more I give throttle it drops to run on 5 cylinders and if I give it more it drops down one more! I changed the fuel Filter, injectors,plugs,wires checked the spark and sparks on all 6 at idle.. I don't know what is wrong with it.. Thinking it's the throttle position sensor.. Someone please help me! Thank you..

[butch]

A throttle position sensor will not cause and engine misfire. A misfire under load is usually because of and ignition problem. Usually a plug wire or two. You have replaced all of the ignition parts except the coils. You can spray water on them to see if you can cause them to break down.

Another possibility is plugged Catalytic Converter. This can give the feeling of a misfire, but if you are looking at live computer data, then you would not see an actual misfire. Maybe you just think it is misfiring. Disconnecting the exhaust before the converter is the best way to tell. If it is plugged, the engine will run great after disconnecting the exhaust before the catalytic converter.

Also, try unplugging the MAF sensor. This can also give a poor acceleration problem.

Have the fuel checked for high alcohol content.

[david w]

1977 chevy 350. motor screams as rpm go higher. sounds like a belt but its not. changed belts water pump generator. rebuild edelbrock 600 even tried to see if harmonic balance had any give to it. any ideas........

[butch]

I assume you removed the belt and the noise went away? Use a stethoscope to try to pinpoint the noise. If the noise is there with belts off, then i would be looking at internal engine problem- timing chain, cam bearing, etc.

[Ebony]

Hello. I recently changed the head gasket on a 1998 ford escort. I put new spark plugs, new timing belt, and a new fuel pump. The car sounds like it wants to start but isnt catching last minute. I know its not the crankshaft sensor. I recently changed all my head gaskets on a 1998 ford escort. I put new spark plugs timing belt and fuel ect. The car sounds like it wants to start but isnt catching last minute. I know its not the crankshaft sensor cause the wires sparked still. I know its not timing belt. Car will crank and crank and even turn over fine but will not start. What could it be?

[Terry]

You say you are sure it is not the timing Belt? Are you sure you have the engine timed properly with the belt? Maybe the cam and crank shafts are out of time. That is the most common cause of a car that wont start after headgasket replacement.

[David9000]

I could use some help.. my truck is a 89 gmc s15 it won't start unless I spray starter fluid in the carburetor I have replaced the Relay the computer and the the injector on thar carburetor. . Still won't start and everything has power. What should I do?