P0300, P0403 Check Engine Codes
 

I just got these P0300, P0403 Check Engine Codes; I am a low income adult with disabilities and it will take me several weeks to try to scrape together the monies needed to get these codes fixed. Can I drive safely with these codes?--just for a few weeks?

Its a random mis fire and low voltage to the egr valve, How is it running?

TH

Lil Rough--Nothing Major
 

It's running just a Little Rough--Nothing Major-
-has Not Stalled Out - Nor Does it Sound Like It Wants To

The solenoid is under $20 or you might just need to clean the valve. You won't know what's causing the misfire until the valve is fixed.

TH

Is this something I can do myself?
 

I don't have a service manual, is this something I can do myself?--the solenoid? Clean the valve? Is there some type of liquid or spray that I can add to my gas, oil, etc - to help alleviate the situation?

And, is it safe to drive,
or am I looking at stalling out sometime real soon?

AS long as the misfire is not severe enough to cause the check engine light to flash , you are ok driving around with the light on. I would concentrate on the PO300 code as that will affect your fuel mileage. Have you ever replaced the spark plugs?

not yet--will do today
 

will replace spark plugs today

if it was me, new plugs, wires, replace air filter, clean your mass air flow sensor in the intake boot first to eliminate all of those and it has probably never had them done.

i had a p0300 that was recurring for a while, ultimately- a crank relearn at the dealer ended up fixing it for me but i finally had to take it in to have it done. it would go away after a good cleaning of the MAF sensor.

an egr valve can be cleaned/replaced with some mechanical know how. i wouldnt think they are super expensive, might be worth asking when you get your plugs. might be easy enough to just change it while up inside changing everything else.

steve

PO300 and also lower back lights not working on lower dash temp knobs
 

I had a PO300 code engine light on my 2006 H3 220000kms. I don't actually get any drivability issues.. Starts up nicely when I unlock my door with key and don't use the FOB to lock or unlock.. That being said I have to wait 10 minutes to start if I forget and use keyless entry or autostart. Anyways back to the P0300 code. I guess spark plugs are best to check? Because its P0300 then its not just 1 cylinder its on different ones.. Based on this what would the educated guess be? I reset engine code and drove 200kms and no engine light but I also ran a full bottle off seafoam before I reset the code. Any correlation? Oh yes and im new to the forum and new to hummer ownership.. Cheers

Taptexas
 

Gentlemen My mechanic has tried everything short of pulling the heads off. My PO300 engine code will not go away. I have a 2006 H2 SUT with 157k miles on it. I'm the only owner. It is misfiring on the left side only particularly the 1st and 7th with only 160 psi. We have changed the spark plugs, wires, PCN, PCN hose intake gasket, and it past a compression test. We even followed someones advice and did a crank relearn and cleaned the MAF sensor. The engine warning light is always on and some times blinks. My drive around town gas mileage has gone from 12MPG to 8MPG. My mechanic is affraid that I could mess up the catalytic converter if I do not figure it out soon. If I take it to the dealership they are just going to say do a tune up which we have already done. PLEASE does someone have any ideas?