As was mentioned earlier in this thread by “Guyfang” I believe, a notable difference in temperature on the exhaust manifold ports by using your hand would indicate a problem cylinder. A difference in manifold port temperature as measured with an infrared gun may just be incidental. Have you allowed this engine to reach operating temperature yet? If not, I would do so. That is unless the engine oil pressure is low. (We still don’t know what that is yet?) The reason for allowing the engine to operate up to normal operating temperature is because many times these cold engine misses will clear up. Especially on an engine that hasn’t seen any hours on it for a while. Once the engine has reached normal operating temperature, if it still has a miss, or if you can still feel/see a big difference in exhaust manifold port temperatures, now you can begin the trouble-shooting process on that. With the engine running (again, as Guy has previously mentioned) simply crack open the high pressure line at the injector for cylinder #1. (It’s like removing the spark plug wire from cylinder #1 on a gas pot engine) If there is a change in the sound of the engine with that line cracked open, close it and move on down to cylinder #2 and so forth and so on. When you crack an injector line loose (on an engine that’s up to operating temperature) and the engine sound does not change, that’s where your problem is. Now you get to find out if it’s an injector problem, a valve problem, a problem with piston and/or rings etc. My suspicion is that this engine will clear itself up when you allow it to run up to full operating temperature. (For clarification, that would be at least 180 degrees on the temperature gauge, or until the temperature gauge doesn’t go up any further) Report back, good luck and have fun too! Oh, BTW…please, please wear eye protection when cracking open those high pressure lines on a running engine!!!
