2004 Avalanche Check engine light flashing
August 13th, 2019, 11:14 PM
#13
misfire monitors show which cylinders are misfiring in live time. it helps you isolate the misfire to a specific cylinder. if you can't view this will a scan tool I would perform a compression test as the next step
September 14th, 2019, 9:46 PM
#14
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AFM Equipped?
Does your truck have active fuel management? This is where truck drops 4 of the cylinders operation during driving when the ECM determines they are not needed based on certain driving criteria. I'll reserve my opinion on this "feature" of truck and just give you another plausible cause.
First check to see if cylinder 4 is a regular cylinder or an AFM cylinder. If it is an active fuel management cylinder (and I'm pretty sure it is) based on my experience, you may have a stuck lifter. Not good. This is an internal engine part and requires extensive service to fix. However, I am not a mechanic in the least, and I was able to change out this faulty lifter myself (with the help of forums and you tube) but it took me a very long time, days, maybe even a week to do so. I think dealer service book says 8-10 hours, for me I'm always triple dealer time but the part itself is cheap (although not in comparison to regular lifters) about $50 and to save $12-1500 in labour costs I simply had to do it myself, there was no other option. I can go into detail about why part failed if needed but in this instance and to just try and stick to helping you figure out issue it's not needed. If this turns out to be your problem I would be more than happy to suggest what to do and route to take. In short, fix it, disable the AFM system BEFORE you even drive it one inch and next truck you buy ensure it does not have not only a feature that does not do what it claims to do but also one that will not cost you a pile to fix when it's modified parts fail. And nevermind the downtime and inconvenience it causes.
First check to see if cylinder 4 is a regular cylinder or an AFM cylinder. If it is an active fuel management cylinder (and I'm pretty sure it is) based on my experience, you may have a stuck lifter. Not good. This is an internal engine part and requires extensive service to fix. However, I am not a mechanic in the least, and I was able to change out this faulty lifter myself (with the help of forums and you tube) but it took me a very long time, days, maybe even a week to do so. I think dealer service book says 8-10 hours, for me I'm always triple dealer time but the part itself is cheap (although not in comparison to regular lifters) about $50 and to save $12-1500 in labour costs I simply had to do it myself, there was no other option. I can go into detail about why part failed if needed but in this instance and to just try and stick to helping you figure out issue it's not needed. If this turns out to be your problem I would be more than happy to suggest what to do and route to take. In short, fix it, disable the AFM system BEFORE you even drive it one inch and next truck you buy ensure it does not have not only a feature that does not do what it claims to do but also one that will not cost you a pile to fix when it's modified parts fail. And nevermind the downtime and inconvenience it causes.
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