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frank, Chevrolet Technician
Category: Chevy
Satisfied Customers: 3420
Experience:  33 years experience,24 years of Chevroler/GM experience and training .ASE Recertified Master Tech,
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2002 cavalier: random multiple cyl misfire..trac..fuel filter

Customer Question

2002 Cavilier- Diagnostic code PO300pd MOD$10-random multiple cyl misfire,check engine and trac off lights illuminated. New fuel pump,fuel filter,plugs and fuel pressure regulator within the last 14 months.Car has 115000 miles,ran great yesterday,started this am and problem occurred.Very cold here but car was in garage ovenight.
Submitted: 9 years ago.
Category: Chevy
Expert:  frank replied 9 years ago.
A p0300 is a missfire-that code will cause the trac light off and the check engine light on.A miss fire can be caused by a a fuel air mixture problem or ignition.The fuel could be a injector or a vacuum leak-ie intake gasket or injector seal and the ignition could be a plug,wire or coil.You need to do some ching to see which cylinder is not carring its fair share of the load and consentrate on that cylinder.A sporadic miss that you can feel come and go is usually a electrical problem,.
Customer: replied 9 years ago.
Not a sporadic miss,consistant and constant miss. I would need more detail on what to do. Thanks, XXXXX XXXXX respond back untill tonight.
Expert:  frank replied 9 years ago.
Statr by locating the dead cylinder then see if it has spark -after that swap spark plugs.Look for a disconnected vacuum hose and check for a intake leak-you donot have the equipment to test the injector for flow so that is a last effort.
Customer: replied 9 years ago.
Reply to frank's Post: This engine is a 2.2 ecotec with an ignition coil pack bolted to the valve cover making it impossible to test spark without special testers I suspect. I used a stethascope and could hear all 4 fuel injectors ticking.Pulled off ignition coil pack-plug boots looked normal.Pulled plugs and it appears cyl. 2 & 3 were possibly wet.Suspect possibly faulty ignition coil pack or ignition control module--- can they be tested off of engine and who would be capable? Thanks-hope we can fix
Expert:  frank replied 9 years ago.
If you remove the cover and have a set of extra plug wires you could run it from the cover to the plugs and check for spark.The module drive the coils.You could also try disconnecting the injectors -cylinders 1&4 and 2&3 are fired in pairs.A bidirectional scanner like a tech 2 can do a injector balance test and cylinder balance test thru the scanner.
Customer: replied 9 years ago.
Reply to frank's Post: Do not have extra wires.My scanner is an actron cp9145, did a quick look in manual, did not see anything about balance tests. Do you know if ignition coil pack can be tested by anyone? At this point this would be my best option for tommorrow as it is getting late and I have little time to spend on repairs during the week. Thanks
Expert:  frank replied 9 years ago.
The dealer is suppose to have the tool to check it-just trying to find some one that actually know where it is or if it got sent back-your still at the is it spark or fuel and which cylinder it is.Try listening to the injectors and see if there is a audible diffenence and disconnecting 1 at a time to see which cylinder is dead.
Customer: replied 9 years ago.
Reply to frank's Post: Frank, I questioned a recommended local diagnostic tech who felt the problem most likely was the ignition control module. I replaced it and problem solved. I feel that I now owe him a payment of some sort.I sincerely XXXXX XXXXX for your input.I will not hesitate to use your expertise in the future.Your input unfortunately did not solve my problem, which I know is not easy in this format when I may not have the tools or knowledge with some of the technical info you suggest.If you strongly feel I should accept your answer, I will consider. Again THANK YOU and maybe we will have success with my next problem. Dave
Expert:  frank replied 9 years ago.
After all-this is the internet and I am not there to do any diagosing-It is the opinion of the site that if you are not satisified you do not have to pay-thank you for using just answers and think of us again in the future.