p0300 random misfires. just at idol, truck runs fine wide open. when problem first started i replaced sparkplugs( acdelco) and cleaned TB and MAF sensors. it ran great for about an hour, then problem started back up again. its been 2 weeks and now its to the point where i have to increase throttle to over 1000 rpm at a stoplight b/c of the constant misfires
Country: United StatesMake: ChevroletModel: Colorado WTYear: 2006Engine: 2.8 lt
truck just hit 100,000 miles. replaced belts plugs air filter flushed coolant and switched to mobile 1
Hello, I'm Cam. Please include all the details about your issue so I can accurately advise you. I cannot see your vehicle so please be detailed.This could be abd likely is a head and valve issue. These are common for the intake valves leaking and causing misfire at idle. The test requires a cylinder leakage tested. This puts compressed air into the cylinder to see how much leaks out. Anything more than 25% is too much.
GM Grand Master Technician 2007. 11 years experience.
would the leak test be something i could do at home without too much down time? if it is the valves. im guessing new valves and springs would be the answer or could they(vlaves) just be ajusted
You can do the test, it only needs the tools to get the plugs out, a wrench to turn the crank and the leak tester with an air compressor. IF the valve are leaking then you will need one of the following, new head and valves, have your head rebuilt with a valve grind. This is not something that can be adjusted out as it is air leaking past when they are closed.