my 99 blazer /120k has a new rough start, idle and drive problem. Basically feels starved for fuel. After going will have reduced power (slightly) and misses at times. I do not have black smoke (rich mix) and I do hear the whine from the pump. The strange thing is it seems to do much better with a full tank, under half it sucks. I also have the popular fuel gauge problem. My engine temp is always low - around 150 - so also plan to replace engine coolant temp sensor - have read it also causes this problem. I also randomly get the service engine light - code to replace bank two oxygen sensor. Dont use premium, and have considered used fuel cleaners but concerned about my high mileage.

My plan is to

1) replace fuel filter ( never been done -got truck with 90k ) and check fuses.
2) Test the fuel pressure and try to isolate which part is failing (pump, or regulator - any more parts to this??) - also dont know if ICM can play a role in the problem. dont know how to test icm anyway -
3) if everything passes then I guess its out of my league

Questions

Are these steps correct, is the fuel gauge related to a larger problem (ie -rust , bad connects ) in the tank, is the oxy sensor or engine temp sensor involved.

Finally any tips on a good pressure tester - or how best to get it done would be appreciated. I hear autozone can test your icm?

Wifes car so under extreme duress !!!!!!!! Wish I could just replace everything.

 

in reading the sticky on fuel system diagnosis, and also in other threads there is mention of (1) the oxygen sensors can cause fuel problems ( i guess in the mix) and (2) the ignition control module. I already have the service engine light and code for the bank 2 oxygen sensor - but always thought it was downstream in emissions - but now understand it feeds back to the ecm and engine performance.

Am I over thinking this and should simply proceed with new filter, pressure test and diag of fuel system and if passes then proceed with these other items.

Thanks, going to AZ for a pressure tester and filter tonight.