I have a 1998 Chevy suburban with trouble codes 172,175 rich on banks1 and 2 and 300 code multiple cylinder misfire. I have changed plugs,wires,cap and rotor and electronic egr valve. Help please .


Asked by Apr 01, 2013 at 01:41 AM

Question type: Maintenance & Repair

9 Answers

Next thing comes to mind is 02 sensor, that will cause it to run rich

Yeah after looking up P0172 and P0175 it does not specify 02 sensor, only the vague 'rich on banks 1 and 2 " just like you already know Oben. "fuel trim system" which does include 02 sensors but other components as well.

2 out of 2 people think this is helpful.

A code P0172 may mean that one or more of the following has happened: The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters can cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry. There could be a vacuum leak. There could be a fuel pressure or delivery problem Possible solutions include: Inspect all vacuum and PCV hoses, replace if necessary Clean the MAF sensor. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling Inspect fuel lines for cracks, leaks, or pinches Check the fuel pressure at the fuel rail Check the fuel injectors, they may be dirty. Use fuel injector cleaner or get them professionally cleaned/replaced. Check for an exhaust leak before the first oxygen sensor

2 out of 2 people think this is helpful.
Best Answer

I have already cleaned my maf sensor, check vacuum steady at 18-20 . New exhaust no leaks in it. At idle runs rough but smoothes out driving and has very bad gas smell out the exhaust.

Hmmm. I looked up P0175, and it says the very same thing, so no need to re post it. I will try another source and see if I can find another fix

This is good. Go read: http://troubleshootmyvehicle.com/gm_P0172_P0175_4.3L_5.0L_5.7L/rich_fuel_tests_1.php....it's a really good article, right on target about your trouble

3 out of 3 people think this is helpful.


Also, since those didn't help, I tried P0300 that you wrote and found:..A code P0300 may mean that one or more of the following has happened: Faulty spark plugs or wires Faulty coil (pack) Faulty oxygen sensor(s) Faulty fuel injector(s) Burned exhaust valve Faulty catalytic converter(s) Stuck/blocked EGR valve / passages Faulty camshaft position sensor Defective computer Possible Solutions If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.

However Oben It looks like you have already done most of that.

Your Answer

Add photo

Related Questions

  • Cylinder Misfire code 32 answers

    Hey I was wondering if anyone has ever experienced the engine light coming on and throwing a Cylinder misfire code. I noticed that my jeep would kinda feel like it was jerking through a gear, but real...

    2006 Jeep Liberty


    Maintenance & Repair

  • 1998 Chevy Silverado misfiring rapidly! Help please! 8 answers

    I was driving my truck the other day and it was running fine and all of a sudden it started running extremely rough and misfiring like crazy. It also started running really rich and also gas is lea...

    1999 Chevrolet Silverado 1500 3 Dr STD 4WD Extended Cab SB


    Maintenance & Repair

  • What is the proper operating compression PSI for a 1999 Chevy Suburban c1500 5.7L? 16 answers

    P0300 misfire - cylinders 2, 4, & 6 - already replaced all plugs/wires, cap/rotor, cleaned throttle body, replaced crankshaft sensor, & throttle pedal sensor. Want do pressure test to check for vacu...

    1999 Chevrolet Suburban C1500


    Maintenance & Repair

  • 1999 4.3 misfiring 39 answers

    I'm running out of ideas on a problem with my 99 S10 4.3 The truck will start and idle fine however as soon as you feed a little gas it starts to miss. Giving it even more gas is either covering up th...

    1999 Chevrolet S-10 2 Dr STD Standard Cab LB


    Maintenance & Repair


Search Maintenance & Repair Questions

Maintenance & Repair Experts

#1 Tom Demyan
Tom Demyan
Reputation 163,320
#2 dandyoun
Reputation 89,530
#3 tenspeed
Reputation 72,640
View All