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Hey geniuses. So as you know I’m on here most often and you all know that you guys are my go to for informations.

Here is what I want to find out.
my 7th gen civic is not running that much smooth like I would like it to be. Let me let you know that I have no cell light at all but it’s not as smooth as I think it can be. I just changed my oil, plugs are new from the dealership, pcv valve alo new from dealership, coil packs are not from dealers but they are about 1 year on my car and no visible cracks on the tips that goes over the head of the plugs. I’m using the recommended weight oil, always use 5w20 oil. My gas gauge is not reading correctly as it goes up and down at times, maybe bad fuel pressure readings from the fuel pressure regulator inside the fuel pump assembly. The pump is new and fuel filter is new as I changed those a year or two ago and got some fuel injectors from rock auto, rebuilt type. So, what can I do to make this reliable car runs smoothly because it’s sound a little louder than it should and I have no exhaust leaks anywhere.

 
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Maybe post a video? I'm not getting any tells that anything is even wrong. These aren't insanely smooth engines to begin with, so there may not even be an issue.

 
Rep Power: 210

Check/Adjust the valves. Compression test all cylinders.

 
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Ok. And I forgot to mention, before I changed the engine some months ago it has this high pitch to it especially 1-2 gear but after I put in this other engine I realized that high pitch it use to have is not there anymore but the engine started to over heated so I had to used the head that was on my first engine and so that high pitch that I was getting and the smooth running is not there anymore. I adjusted these values several times trying to see if that’s the cause but no, it still the same. I changed the oil from royal purple to Castro gtx and I realized that it changed the sound a little. Not sure if I can use 5w30 instead of 5w20 to see if that helps but at the same time I don’t want to ruining the engine with that 30 grade oil especially now in the winter.

 
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Again, please post a video. None of what you are saying makes sense.

Just use 5W20. There are very few situations where changing oil weight makes a difference.

Simply changing oil manufacturers will not make a difference. They're all virtually the same anyway. Was 5W20 one of the manufacturers and 5W30 the other one?

High pitch could be a belt that's been overtightened or a pulley. The only explanation (that I can think of) is that your old timing belt was overtightened or one of your old pulleys was beginning to seize. Perhaps your actual engine is just slightly out of time then? That may explain the slightly rougher idle...

 
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ok. I will check the belts . My timing is fine though. 5w20 is the recommended oil and the other is just my choice since it’s a heavier weight.