It's definitely air ingress.

Also CHECK the shut off valve, I replaced every fuel system o ring just to realize that shut of valve was leaking too.

My car would die randomly at idle and be very difficult to start if it sat overnight. The shut off valve was my problem.

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1998 Ford Escort ZX2 5 speed - 279,000 miles My Daily

1992 Mercedes 300D 2.5 202,000 - Pure junk
2000 Mercedes E320 Black - 136,000 miles - Needs repair

Don't forget to grease the screw and threads on the spring compressor.