Are we talking GenI? I would assume so becuase you're talking about pulses. For simplicity, L means long and represents a multiple of 10, and S means short representing multiples of 1 (ie L S = 11) To get these pulses, locate the self-diagnostic connector behind the glove box. Insert negative probe into the bottom left and the positive probe into the top right. Set key switch to ON. Make note of code pulses.
Codes are as follows:
Steady long is the ECU code = $$$
L S = 11 = O2 circuit
L S S = 12 = Air flow sensor circuit
L S S S = 13 = Intake air temp sensor circuit
L S S S S = 14 = Throttle position sensor circuit
L L S = 21 = Engine coolant temp sensor circuit
L L S S = 22 = Crank angle sensor
L L S S S = 23 = Top dead center sensor
L L S S S S = 24 = Vehicle speed sensor circuit
L L S S S S S = 25 = Barometric pressure sensor circuit
L L L L S = 41 = Injector circuit
L L L L S S = 42 = Fuel pump circuit
Repeated S's are Normal State (but you shouldn't have a light on if this is the case <img src="/forums/images/graemlins/smile.gif" alt="" />)
BTW, put as much info about your vehicle as you can in your signature, it shows initiative and helps others help you <img src="/forums/images/graemlins/kewl.gif" alt="" />

Oh, and welcome to the Wire <img src="/forums/images/graemlins/cheers.gif" alt="" />