2002 trailblazer I sold a 03 blazer that run good 246000 bought a 02 it ran great 117000 drove it 2000 mi it's a dog put new plugs new gas new air cleaner looked in exhaust for squirrel nest it ran great I did all I can do I am baffled and a new fuel filter no service engine soon light has appeared what happened

Bleed the air out of the line at the engine intake.

Thanks for the picture! Answers a couple of big questions. "Trailblazer" didn't come out til' 2002 and it came with an Inline 6, not a V6 and an optional V8. This looks like a Blazer with the V6, so if this was taken out of a 2000 Blazer with the V6, you should be golden putting into a 1995 Blazer which came stock with that same engine.

remove dog house locate test port and install guage should be 45-60 psi

If it ran out of gas you'll need to purge the air out of the fuel line. Chances are also good that you pulled some sediment off the tank bottom and clogged the filter. If that's the case you'll need to replace the filter.

More then likely the brushes are sticking in the blower motor.

Thats the mass air flow meter.Should get changed at 60.000 miles. Also change the air filter.

Did you change the fuel filter?

i have 2003 trailblazer ltz 153 000 mileage i have code po440 .i changed gas cap and turned off the chech engine light... i made 300 miles and it was good and today morning i drove a mile and light turned on ..... what do i have to fix ...thanks

Sounds like your timing is off. Try having your timing reset. and new timing chain.

try changing the air filter ,i had a problem ,at ilde in drive my trailblazer would stall, changed the air filter now it's not stalling and got my power back ,there is a secondary air pump that i have to change ,
not sure were it is ? still not running perfect but it's running better .and my service light is on too.
i got it put on scope ,it's the pump .
not sure if this helps ,but i'm start to run in to problems too,i have a 2004 trailblazer.
i like to do fix things myself ,i hope i can.it's the cost if you know what i mean.