So here’s the deal. I got a 1988 Honda prelude 2.0Si fuel injected and I’m trying to smog it but it keeps failing on the HC portion of the test. Keeps blowing 9-35 points too high. I took apart my whole air intake down to the back of the engine and when I put it back together I got 25mpg. Then I heard this metal noise grinding at 3,000rps and both support bracket bolts for the air intake came off so it was just bouncing around and my mph when back down to like 18mpg. I redid the intake again with new gaskets and made sure all the bolts were tight And it went back up to 25mpg. I also got new injectors and ran it for 120 miles when I heard a different metal on metal noise around 4,000rpm, my brackets are all tightened down and no bolts are missing but my gas mileage has gone back down to 18mpg!!! Can anyone tell me wtf is going on and what could be the issue? I thought I was having an air leak but could my fuel rail be bad, am I just not doing a good job putting it back together? I’m going to buy new gaskets and restart tomorrow. Any input on why my mpg fluctuates would be greatly appreciated!