Help, please

First, let me apologize if this is a stupid question or if it's been asked already (I searched, but I didn't find anything). My boyfriend has a '90 Acura Integra, and one of his friends took it for a rough ride 2 days ago. Well now when he hits 3 RPM's it starts making a popping sound. The best way I can explain it is you hear the rev, and then pop! pop! pop! pop! Anyone have any idea what it might be?

Also, we live 45 miles away from any car mechanic type place, so considering his car sounds like it wants to die when we hit 3 RPM's, does anyone think we would make it? Thanks in advance for any help :)

sound like detonation (fuel ignites b4 it is supposed to.) the first thing i would do is a tune up.
Plugs/wires
timing
check the coil
make sure there is a strong enough spark.
if it is vtec high octane fuel, not vtec midgrade fuel

does he have an exaust system. sometimes the exhaust pops when letting off the gas pedal.

Well, a week ago or so his exhaust/muffler came loose so he took it off because it would randomly drag on the ground while he'd be driving. We're replacing it tomorrow, if we can get the car to go anywehere. The only reason I didn't mention that before is because other than being louder, it didnt start acting up until 3 days ago when they went on that ride (and he's never driven it that hard before), so I didn't even think about mentioning it. So, does the muffler thing explain what it is doing now? Oh and in case this piece of info helps, since yesterday he's had trouble starting the car altogether. If he tries long enough it eventually comes on, though.

I'd LOVE to get a tune up, but I'm scared of driving all that way to get it done and have it break down on the way. There's really nothing between here and there, so I'd be screwed lol