My 2000 S10 has no power, I get two codes, 154 and 300. I have been chasing vacuum leaks but I'm not sure that's the problem. It shakes and vibrates when trying to climb hills and when the RPM's get around 2500 or above my check engine light starts flashing. I am having a lot of trouble chasing this issue, any help would be greatly appreciated. Thanks for your help and expertise.

 

Sorry i can't help much but one thing i know is that a flashing check engine light is not good at all and could me serious problems. I suggest not to drive it till you get someone to look at it or figure out the problem.

any small engine codes like misfire, etc will be stationary lit, but when the engine needs immediate attention, it'll start to flash.

 

when your check engine light flashes, that means that you are burning up your catalytic converter. If you keep driving it with the light flashing, you are going to ruin the cat and possibly have the car not run at all, or at least run like crap cuz you just restricted your exhaust lines. then you'll really have problems.

I am not sure what p0154 is, but p0300 is multiple/random cylinder misfire.
When is the last time you did a tune up?

Is yours the 4.3L? If so you are going to want to do the cap and rotor as well.

 

I just did cap, rotor, wires and plugs. Also replaced the air filter, pvc valve, water pump and entire cooling system. Will check into the cat tomorrow. Thank you.

 

Have a read through these two threads:

P0154 Explained

P030x Explained (x=0,1,2,3,4,5,6)

OBDII systems (like yours) use codes with a letter and 4 digits. Since you already have a thread that involved these same two codes, I have combined your two threads.