Do ECM. Control fuel and coil and adjust fuel ? 2. Does it have a chip on key?

Possible fuel pressure regulator. Also you could do a fuel bleed down test to check for leaking fuel injectors.

Then why I get too much fuel in spark plug ?

It odd. It does not have fuel filter. I. Call dealership they told me I have. No filter because of factory make and now I will check fuel regulator pressure. Try look at it and I don't see anything I did look YouTube I see. But my truck not show me where it should be at ...." Grr" so. Help me lol

Because it could be faulty injectors, leaking, so the fuel would drip instead of spray into the cylinders, so you don't have the proper air fuel mixture, flooding out so to speak. Should do a fuel bleed down test & pressure test. You can rent a fuel pressure gauge from the parts store. Fuel pressure should be 56 to 63 lbs if this is a V6 or a V8 engine. Once fuel pressure is built up, turn the key off and watch the pressure gauge. It should not drop more than 5 lbs in 3 minutes.

4.2 l and it does not have fuel regulators pressure and. Found out throttle body no good and catalytic converters is clogged and. That why fuel built up won't. Get through the air into the pipe so I plann remove catalytic converter to put straight pipe for now and replace it later to test. The air

In those year of 2005 Chevy trailblazer. 4.2 l domes not have fuel filter and fuel regulator pressure it run by fuel pump it weird calls factory make and no key chips too

Thats weird, I'm showing a fuel regulator & fuel filter for the 2005 4.2L engine....and as far as I know all fuel injection have a fuel regulator.

Yeah u right. Not one of those month. It. Don't have fuel regulator I agree with u I went. Dealership they tell me I am one of person. That don't have it it run by fuel pump that all. And I took code reader it. Said throttle body bad and catalytic converter is low mean clogged mean I have to get. New throttle body and new catalytic converter too will u date next grr lol

Is it safe to remove catalytic converter and put straight pipe for while?

It is possible the catalytic converter is plugged, you will not find anyone to put a straight pipe in place of the cat. but you could do it yourself. The engine will throw all kinds of codes but you should be able to make it to where you are going. If the straight pipe makes the engine run, then the cat will have to be replaced. Once that is done then you can clear any codes that turn on the check engine light.

I have a 2005 Chevy Trailblazer that out on the highway it gets 23 mpg but driving locally the gas mileage sucks. Need help it might be running to rich but while it is being driven it runs smooth, but sitting at an idle and in gear it runs a little rough. What can I do to fix this problem. Please email me back at wfrazier1963@gmail.com