My Volvo 200 (Chevy 305) runs great at 3700 rpm for about 20-25 minutes, then I'll feel the first stumble. A couple of minutes later, another, only more noticeable. The pattern repeats until the motor is cutting out and I’ve lost speed. The motor eventually dies, but will almost always restart as though nothing happened. Then it will run fine at lower rpms for the rest of the day. If I let it cool completely, I start from the beginning. After warm up, the temp gauge hold steady for the entire trip. <br />Fuel system has been completely replaced (except for tank which was pulled and cleaned, and four barrel Edlebrock which is recent installation).<br />Ignition looks good (points and condenser), plug wires soft and strong, wiring and connections good. <br />I’ve run gas from different stations and use a filter. I had a water separator on it but removed it due to the plastic bowl (not for I/O). Removal made no difference.<br />I put in an in-line fuel filter (yes I know, illegal) for testing purposes. When the cutting out occurs, air can be seen in the glass. I’m not sure if this is the cause, or a symptom.<br />Like I said it runs great for the first 20-25 minutes. This has been going on for months and I’m getting a lump from banging my head on the wall. I’d spend the money on a mechanic, but good ones for troubles like this are hard to find.<br />This happen to anybody else?