hey whats up..........i got a 99 blazer 4.3 liter 5 speed thats been runnin like total crap just recently....i changed the fuel pump about a month ago.....oil about 3 weeks ago......thermostat a week ago.......and i still have really slow pick up and acceleration........any ideas as 2 what the problem could b?

 

o and i threw it on the obd2 and it was throwin the code p0452

 

p0452 == Evaporative Emissions Control System Pressure Sensor Low Input

This could be caused by a vacuum leak. If you have a vacuum leak, then additional air is being sucked into the engine that the MAF sensor is not accounting for.

 

ight.....so whats the easiest way 2 find the leak and fix it?

 

Well considering that you recently replaced the fuel pump and your code is P0452 I would start there with the tank pressure sensor. And any vacuum lines/fittings associated with the Evap system on the intake manifold...then work on other rubber lines in the vacuum system...

 

Yeah, you basically need to go over the vacuum lines on the engine and make sure that they are all set. It is possible the code and the symptoms you are experiencing are not related, but since the gas tank is put under vacuum pressure by the EVAP system which gets its source from the engine vacuum, there is a possibility that they are connected, especially if the seal on the tank isn't right and the EVAP valve is just open...

Hopefully this doesn't mean that you'll have to drop the tank again, but...

 

If I remember reading fuel pump threads correctly and researching fuel pumps, the pump housing is plastic and if when replacing a fitting or remounting the tank the housing became cracked it would cause this condition...I hope for your sake it is just a vacuum line. Check to make sure that your Evap system lines are still connected "securely" (pushed on all the way), if they are not completely on it may be misaligned allowing vacuum to leak past the connection...also check the line to the Evap tank near the fuel tank....it is also possible the Evap Purge Solenoid is weak and needs replaced....