blinking service engine light

[eeore39648]

I drive a 2000 frontier, 184,00 miles with no problems. Except a blinking service engine light. the truck runs great, like it did new. i have had a diagnostics run on it, twice. no problems according to the diagnostic test.the light binks faster at times, slower at other times. sometimes not at all. then it starts again.since the truck still runs great, i have not worried about it, the light is annoying.has anyone seen this?james

[Desert Rat]

You've had codes pulled and it's coming back with nothing?

[eeore39648]

thats right, no codes are stored.

[NM50]

If the light is on there has to be a DTC. A flashing MIL indicates that catylist damage is ocurring.

[eeore39648]

i was afraid that might be the problem. at cold start, the first few minutes, i hear a exhaust leak, in that area. i have not taken the heat sheild off to inspect, the bolts are rusted from age. and the catalyst is not cheap!what harm, if any, is occurriing? shoot me straight! i have checked on a catalyst, $500. if it is to be replaced, just as well replace the entire exhaust system, right?thanks for your post, it has been helpful!