Emissions Help

Hi, I have a 97 Tahoe. It's currently throwing codes P0300, P0172 & P0175. 300 is multiple misfires and the other two are running rich bank 1 & bank 2. I've heard that the throttle poisition sensor can take care of the misfiring issue and I've heard several different things on the running rich issue.

Please let me know if you've experienced this and fixed it or heard of any of theremedies that I'm about to list and if they work. I heard an EGR valve can fix it. I've heard running a bottle of fuel injector cleaner works. I've also heard that replacing the injectors themselves is the cure and finally that an O2 sensor will fix it, but I think it throws an additional code if the O2 sensors are bad. Please let me know if anyone has any ideas. I've purchased plugs, a pcv valve a fuel filter,and an air filterso far. I replaced the wires about a year ago, so I know they're good. I don't think this is gonna fix it, but it needs to be done. I have to go to emissions and I'm sure I'll fail with the truck running the way it is right now.

Oh a couple other important notes, the truck idles at about 600 rpm right now and the fuel mileage is about 10 or 11 miles per gallon. It runs terrible. Thanks for any help.

Fix thar missfire.
Go a good secondary ign tune up.
AC delco plugs cap and rotor and good plug wire.
Check and confirm good fuel pressure.

Hi, I have a 97 Tahoe. It's currently throwing codes P0300, P0172 & P0175. 300 is multiple misfires and the other two are running rich bank 1 & bank 2. I've heard that the throttle poisition sensor can take care of the misfiring issue and I've heard several different things on the running rich issue.

Please let me know if you've experienced this and fixed it or heard of any of theremedies that I'm about to list and if they work. I heard an EGR valve can fix it. I've heard running a bottle of fuel injector cleaner works. I've also heard that replacing the injectors themselves is the cure and finally that an O2 sensor will fix it, but I think it throws an additional code if the O2 sensors are bad. Please let me know if anyone has any ideas. I've purchased plugs, a pcv valve a fuel filter,and an air filterso far. I replaced the wires about a year ago, so I know they're good. I don't think this is gonna fix it, but it needs to be done. I have to go to emissions and I'm sure I'll fail with the truck running the way it is right now.

Oh a couple other important notes, the truck idles at about 600 rpm right now and the fuel mileage is about 10 or 11 miles per gallon. It runs terrible. Thanks for any help.

what about the distributor ? cap/rotor ? check for condition ,arcing , unusual wear. check for excessive lateral movement.

how many miles on this 5.7L engine ?

There are 125,000 miles on the engine. I'll check out the distributor and see how it is. Thanks for the tip

It sounds like a fuel pump or fuel filter very common if that is what it is be sure to use a GM pump for some reason that is one part you do not want to use after market on. I did and I had to replace it in less than 30 days. Don't make the same mistake I did.