98 blazer and i also have code po300 starts hard then knocks and stumbles on hard acceleration when put in gear or come to a stop it sounds like its gonna die. have put many hours and parts into it.and last thing i think is left to try is i heard maybe valves sticking. please help if anyone has any creative ideas!!!!!

 

*Moved to a new thread of your own*

In an effort to save time and not suggest what you have already done, how about you list out what efforts you have made to this point and their outcome. The more information the better.

 

replaced upper intake gasket , egr valve, dis, cap, rotor, plugs and wires, fuep pump, ign. module, coil ,throttle position sensor, fuel pressure regulator and spider injectors and noe checking the readings on the check cranshaft sensor. still same problem hard start but idles fine give her gas and she throws a knock and stummbles. when put in gear sounds like shes gonna die. fuel pressures within range

 

If you have a scan tool handy, you could monitor the knock sensor to make sure that it is operating properly. A faulty KS shouldn't cause a hard start, but if the timing were out of whack, it wouldn't bring it back in line.

When you tested the fuel pressure, what was the specific reading on the gauge? How long did the pressure hold after the pump shut off?

 

going to get scan tool tomm and will try that.and pressure was i believe 60 and dropped to 55 after warmed up my mechanic friend whos helping me isnt here at moment he'll remember exactley what it was. will also be replacing crankshaft sensor tomm. it only reads out at 326ohms and book said should be between 800 and 1200. thanks for your reply im going nuts with this.