CEL flashes while driving

[Cradle the Dark Side]

I've a '91 Civic HB with a b16 swap. Swaps been in almost 3 years no problems (other then a slight lope in the idle at times). Recently, once the car has been running (usually once driven about 5-10 minutes) the check engine light (CEL) starts flashing continuously. Sometimes it'll stop for a couple of minutes but then starts right back up. I've tried checking the codes but nothing comes up, when the cars first started the CEL isn't even on. I've heard that its a warning sign that the fuel pump is getting to go out but I haven't been able to confirm if this is true. I'd like to find out before spending all that money on a pump and removing the gas tank. Does anyone know for sure or have any others ideas what might be the cause? I've checked the voltage to the pump it seems to be fine so that should eliminate the main relay being the problem. I'd appreciate any help, thanks.

[Siege911]

do you have a helms manual for the 88-91 civics or the gen that your b16 came out of? That could tell you... the only one I have is for a 6th gen, and I'm guessing your swap is older due to the cable tranny.

[Cradle the Dark Side]

No, all I have is the haynes manual, which is essentially useless. I've found all kinds of codes and such online but nothing that says what it means when the CEL flashes only while driving.