Misfire when running above 60
#1
![Default](/forum/images/icons/icon1.gif)
I have a 04 chevy avalanche I keep getting flashing engine light when I run above 60 usually down hill misfire code p0300 I have done the spark plugs wires and coil packs. I did the cam sensor and crankshaft sensor that's when it started throwing codes. I added a couple ground wire to the tps sensor and a couple other spots which where a problem before I did the sensors. If anyone knows what the problem can be let me know. And there is no water in the gas and have good fuel pressure
#4
![Default](/forum/images/icons/icon1.gif)
iif the cats are clogged...the exhaust can't escape out the tailpipe....no air out equals no air in...the engine is a air pump. unscrewing the o2 sensors from the exhaust allows a place for the exhaust to exit.
yes 02 sensor codes will set but if the engine runs smooth and the flashing cel/ misfires are gone...you know what the problem is.
if a mechanic want to test for restricted exhaust...he/she would remove the 02 sensor and screw a pressure gauge into the hole to measure the amount of backpressure. Since you don't have a gauge...you test it by driving it.
yes 02 sensor codes will set but if the engine runs smooth and the flashing cel/ misfires are gone...you know what the problem is.
if a mechanic want to test for restricted exhaust...he/she would remove the 02 sensor and screw a pressure gauge into the hole to measure the amount of backpressure. Since you don't have a gauge...you test it by driving it.
Thread
Thread Starter
Forum
Replies
Last Post
buddyleno
Silverado, Sierra & Fullsize Pick-ups
4
March 31st, 2017 8:13 AM
Davidsednothing
Silverado, Sierra & Fullsize Pick-ups
2
December 6th, 2014 9:23 PM
chevy619
Silverado, Sierra & Fullsize Pick-ups
8
December 2nd, 2012 7:39 PM