Throwing Up Codes

[khmerxrom3o]

Went to Auto Parts and had them do a scan and the codes are PO171 and PO174 Bank 1&2 are too lean also had PO420 Bank 1 catalyst eff below threshold. Was told that i needed to run a dyno :o due to the fact that my car was running too lean. I just clean the MAF and now my car putts when im driving. Cuts off when i make a full stop. NEED HELP

[smooth1]

A dyno? Who told you that?

You probably just need to replace the 02 sensors. But you might want to bring it in to the dealer first to confirm. If the 02 sensors aren't working, then they are sending the wrong signal to the ECU causing the lean/rich air mixture.

[khmerxrom3o]

an auto part worker aka mr WRX STI do you think i need to replace all four or just the 2 fronts?

A dyno? Who told you that?

You probably just need to replace the 02 sensors. But you might want to bring it in to the dealer first to confirm. If the 02 sensors aren't working, then they are sending the wrong signal to the ECU causing the lean/rich air mixture.

[smooth1]

an auto part worker aka mr WRX STI do you think i need to replace all four or just the 2 fronts?

A dyno? Who told you that?

You probably just need to replace the 02 sensors. But you might want to bring it in to the dealer first to confirm. If the 02 sensors aren't working, then they are sending the wrong signal to the ECU causing the lean/rich air mixture.

It's hard to tell from here. You'll need to take it in and have them scan the ecu and test the 02's to figure out which ones need to be replaced and which ones are miss reading because of the fuault codes. DO NOT RESET THE ECU!!! The tech will need to read the info there to make it easier. the hand held scanners at the parts stores only read the codes and can interpret the basic info. the scanners the techs use at Toyota can tell them much more info. You probalby have a heater wire issue. It's a known problem. If they say they have to replce the 02's, you can buy them on ebay pretty cheap, but make sure you stay with Denso's. Don't use Bosch or some generic, as Denso's seem to be the only ones that work right.

[khmerxrom3o]

an auto part worker aka mr WRX STI do you think i need to replace all four or just the 2 fronts?

A dyno? Who told you that?

You probably just need to replace the 02 sensors. But you might want to bring it in to the dealer first to confirm. If the 02 sensors aren't working, then they are sending the wrong signal to the ECU causing the lean/rich air mixture.

It's hard to tell from here. You'll need to take it in and have them scan the ecu and test the 02's to figure out which ones need to be replaced and which ones are miss reading because of the fuault codes. DO NOT RESET THE ECU!!! The tech will need to read the info there to make it easier. the hand held scanners at the parts stores only read the codes and can interpret the basic info. the scanners the techs use at Toyota can tell them much more info. You probalby have a heater wire issue. It's a known problem. If they say they have to replce the 02's, you can buy them on ebay pretty cheap, but make sure you stay with Denso's. Don't use Bosch or some generic, as Denso's seem to be the only ones that work right.

when my car idles it fine but when i drive and let it ride, it starts to act funny meaning the rpm gauge drops down below 1. i was told not to drive my car anymore. :( not sure what to do now.

[smooth1]

The car may have gone into a limp mode, which is designed to save the engine and protect it. But again, I can't really diagnose your car over the web like this. Take it in to a qualified tech to find out what is going on with your car. Once you have that info, then we can be of more help as to how to maybe save you some money and get it fixed.

[khmerxrom3o]

i just dropped off to toyota this morning. hopefully i can get an answer today since they are busy due to the recalls. i was alo told by a friend that it COULD be my knock sensor thats making my car stall.