The hoses kept popping off of my gauge (really exciting with gas and exhaust manifolds) so I'm doing a solid run tomorrow after I get some little hose clamps from the hardware store. The nose-off does seem to be inconsistent - last night I got over 4500 before it started slowing down, earlier today I wasn't even past 4000. Sometimes it feels abrupt, sometimes the engine just climbs slowly without seeming to fall off a cliff. A new Airtex fuel pump plus an adjustable regulator (I understand those pumps run around 7 psi, which is too much for the AVS I have going on soon) will hopefully be a cheap solution to this if the gauge confirms my suspicions at this point.