I have an 02 4.3 starts and idles fine. acts like it not getting fuel after 2k rpm. changed fuel filter . get four codes P0101 , P0102 , P0171 , and P0171. got any ideas.

 

Low fuel pressure and or volume can set those DTC's. Here's the first step: https://blazerforum.com/forum/2nd-ge...eakdown-88305/

Post all 4 readings and we can analyze the results.

 

ok heres what I got port= 64 lbs drops to 56 lbs when shut off then drops t0 50 lbs after 5 min, 46 lbs after 10 min. at the filter when on it pegged the gauge at 100 lbs . I forgot to get it at filter when it was off. I can assume its not the pump ? maybe the regulator? Oh when I changed the fuel filter the fuel continued to flow out of the tank and also did it when I checked the pressure.

 

100psi max pump output is fine. Regulated pressure at 64psi is fine. The drop to 46psi after 10 minutes is a problem. Without knowing what the pressure at the filter is after 10 minutes, you have no idea what is causing the leakdown.

 

ok retested it this morning at filter it took a few turns of the key to get the pressure built up but it read 84 on , 82 off then dropped to 70 after 10 mins. Also the engine light comes on and goes off and it revs to about 2800 to 3000 rpm then starts to sputter.

 

If the pump leaks down to 70psi after 10 minutes, (which is within specs) any drop below that at the service port, indicates a problem in the plenum. Could be an injector, fuel pressure regulator, leaky O ring in the fuel metering block etc. To determine if the regulator is the problem, a shut off valve must be installed in the fuel return line. Pressurize the system, and close the valve immediately after the pump deactivates. If leakdown remains above 55psi for 10 minutes, the regulator needs replacement. CAUTION: If the valve is closed while the fuel pump is activated, the diaphragm inside the regulator will likely be destroyed.

 

Half these codes are MAF related. Have you taken it off and had it checked? O'reillys and Autozone do this for free.

 

checked everything. finally had exhaust check and the rear converter was bad. had them both replaced have not has check engine light come on so far. shop said to have it diagnosed because converter was burned up. thank you for all your help and advice it is much appreciated. sorry it took so long for this reply as I had some other problems come up.(not car related.)

 

The shop gave you good advice. If the converter had a melt down, there's a reason. They melt down because of a rich running condition with the engine, (misfire etc) and it will destroy the new converter if you don't diagnose & repair the problem soon.
Don't put too much faith in the auto parts stores test machines, they are nearly worthless, but they do help them sell parts