So my 03 xlt won’t pass smog. I’ve found that cylinder 1 misfires due to low compression. I’m afraid it’s a valve or piston ring, but I’ve heard it could be the piece that presses the valve is not seated correctly and that if this is the issue I may not have to remove the head. I’m looking for help on what to look for. The truck has 307k on it and I’m told that fixing the valve or piston ring will raise the compression and quite possibly the lower end won’t be able to handle it without causing leaks or worse. I would really like to save the truck and I’m going to spend what little spare time I have trying. Any help would be greatly appreciated.