I have a 1996 accord lx. It has low power and the engine cuts out between 3 and 5k rpm. Ive noticed when it cuts out, puffs of air come through the intake, and not in little quantities. When the engine cuts, gushes of air go backwards through the intake. The mechanical timing is right, and the compression tester read about 160+ psi on all cylinders. What does this mean? Are the valve springs too weak, and floating? Cat was previously clogged (100% clear now) and car has 300k miles.
Video of air going wrong way thru intake : https://youtube.com/shorts/6PQDFIwvSm8?si=8ETzRYy2RQszk_vz

 

I just performed a leak down test and had about 5 to 12% leakdown for each cylinder. Is there any other way the exhaust gas would come through the intake? It also pops and spits through the intake everytime it cuts.

 

If it is exhaust gasses leaking through, check your EGR system for faults. If the EGR valve is opening early or not seating correctly it would allow exhaust gases into the intake.