AboutCAJUNSC/RAMBLER390 Expertise 1998 and NEWER questions ONLY!! I WILL REJECT QUESTIONS FROM 1998 BACK. Electrical diagnosis. Brake Diagnosis. Driveability, Service Engine Soon Lights. Some Engine mechanical. Tires and wheels. ABS. HVAC. Air Bag (SIR). Interior, seats, etc... 6.6L Duramax Diesel diagnosis. 6.5L diesel diagnosis. I WILL not answer Alignment questions OR carburetor questions. No heavy internal transmission
I need YEAR, MAKE and MODEL of vehicle, and ENGINE SIZE and TRANSMISSION type, IF applicable to the question.
I work at a Large, Busy GM Dealership
Last thing, my answers are JUST SUGGESTIONS and ADVICE and you should ALWAYS CHECK with your mechanic for proper diagnosis and repair.
Experience 18 Years GM Dealership experience as an "A" line tech. ASE MasterTechnician. 100% GM paper certified and working towards MTC Certification.
Education/Credentials High School graduate. No College or higher learning.
Expert: CAJUNSC/RAMBLER390 Date: 1/22/2008 Subject: 2001 GMC Jimmy PO300 code
Question I took my vehicle in because the engine light was on. The repair shop ran diagnostics on it and came up with the diagnostic/scanner code of PO300 - random cylinder missfire. The garage just said that it would be $1500 to repair, no specifics - Any idea on what this would be?
Answer Hi
P0300 can be many different items.
ANY fuel, ignition, or engine mechanical problems CAN cause a p0300 to set on ANY cylinder(s).
Stuck injector, faulty spark plug, bad cam lobe...
I would HIGHLY recommend 2 things
1) Take it to another shop, that will EXPLAIN the repairs they are going to preform.
2) I would tell you to have a good major tune up preformed on truck IN ADDITION to any other repairs made. (Spark plugs, plug wires, Dist cap, Dist rotor, fuel filter, air filter, injector power flush and throttle clean).
This MAY also repair your truck and give you piece of mind on maintance needs.
I hope this helps
Pawl
