Error Code P0303 Cylinder 3 Misfire

jtotexas · 04-06-2009, 11:18 AM

I have been trying to get my 1998 Chevy C1500 Ext cab truck to pass Texas Vehicle Inspection; however, I am getting a P0303 Error code. The error code is a "Cylinder 3 Misfire".

I bought this truck from a private seller that had used it for his irrigation business. The truck had 166000 miles on it when I bought it and I only wanted to use is as a work truck that I would just haul supplies for home repair.

I was getting another error code before; however, I fixed that by replacing the Bank 1 Sensor 2 Oxygen sensor.

After I replaced the spark plugs, checked the wires (they looked newer) and cleared the code. I started up the truck and the "service engine light will come one. The "Service Engine Soon" light will come on for a few trips and then go off again for a few trips.

Any help would be appreciated.

mudseeker · 04-06-2009, 11:28 AM

pull the injector harness off the upper intake or find the fuse for them. next, do a compression, spark and fuel pressure test.

might want to find a scan tool and do an injector balance test too.

also check the cap/rotor and swap out the spark plug wire to see if the code follows the wire.

jtotexas · 04-06-2009, 03:13 PM

Is there a quick way to test the distributor cables? I have a digital multimeter that I can use to test the cables if I need too. I have heard that I should get an infinite reading if the cables are good. What do you think? I was also advised to do a spark test. How would I do that?

leolkfrm · 04-06-2009, 03:47 PM

spray the wires with water and see if they arc, if so change them

bradrhale · 04-06-2009, 07:28 PM

Quote:

Originally Posted by jtotexas

Is there a quick way to test the distributor cables? I have a digital multimeter that I can use to test the cables if I need too. I have heard that I should get an infinite reading if the cables are good. What do you think? I was also advised to do a spark test. How would I do that?

test continuity on the wires........ the meter should read as close to zero as possible. spark test......... pull the plug and push it into the plug boot. USING PLIERS WITH INSULATED HANDLES, hold the electrode against a ground (engine block) and turn the engine over. it should be a blaze of fire across there that is blue. you can buy a tester that goes inline with the plug and spark cable that is a little easier than what i have described.

04-06-2009, 11:18 AM	#1
jtotexas Full Member Join Date: Mar 2009 Posts: 10	Error Code P0303 Cylinder 3 Misfire I have been trying to get my 1998 Chevy C1500 Ext cab truck to pass Texas Vehicle Inspection; however, I am getting a P0303 Error code. The error code is a "Cylinder 3 Misfire". I bought this truck from a private seller that had used it for his irrigation business. The truck had 166000 miles on it when I bought it and I only wanted to use is as a work truck that I would just haul supplies for home repair. I was getting another error code before; however, I fixed that by replacing the Bank 1 Sensor 2 Oxygen sensor. After I replaced the spark plugs, checked the wires (they looked newer) and cleared the code. I started up the truck and the "service engine light will come one. The "Service Engine Soon" light will come on for a few trips and then go off again for a few trips. Any help would be appreciated.

04-06-2009, 11:28 AM	#2
mudseeker Senior Moderator Join Date: Feb 2006 Location: michigan Posts: 6,374	pull the injector harness off the upper intake or find the fuse for them. next, do a compression, spark and fuel pressure test. might want to find a scan tool and do an injector balance test too. also check the cap/rotor and swap out the spark plug wire to see if the code follows the wire. __________________ i'd rather be hunting

04-06-2009, 03:47 PM	#4
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,300	spray the wires with water and see if they arc, if so change them __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

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04-06-2009, 03:13 PM	#3
jtotexas Full Member Join Date: Mar 2009 Posts: 10	Is there a quick way to test the distributor cables? I have a digital multimeter that I can use to test the cables if I need too. I have heard that I should get an infinite reading if the cables are good. What do you think? I was also advised to do a spark test. How would I do that?