[davids101]

Greetings,
My Car: 1997 Mustang 3.8 w/5 speed (95 k miles)

Check engine light (CEL) went on 3 weeks ago, No overheating, stalling or sputtering. I re-booted system but CEL returned after 2 days.

Local shop tech diagnosed code set PO175: too rich right bank. Fuel pressure OK, cleaned MAF and throttle body, plugs OK, Oxygen sensors OK. Technician found barometric system a little high (162, should be approx 159). Clear KAM. Car currently has Bosch 4-pronged platinum plugs which tech stated are not OEM and might be part of problem?...he recommends Motorcraft plugs.

Technician recommends driving car for awhile to see if CEL returns. He says if CEL returns I may need to take car to dealer (ugh) to get PCM reflash. He says another possibility is a leaking fuel injector.

Has anyone had any similiar experiences or have advise on how to further diagnose should CEL return....

Any info is appreciated.
Thanks and cheers

[StalkerStang]

Try cleaning the MAF sensor wire with some electrical parts cleaner. The baro can go off sometimes due to the MAF sensor being skewed, although its not very common on the Mustangs, but it is possible. However its just one bank, usually MAF and Baro issues will cause both banks to be affected.

I would agree with your tech, Bosch plugs are crap, no matter if they are Bosch super, +2, +4 or +2054, they are crap. Go with some Motorcrafts for sure, they aren't expensive, or at least Autolites. No need to gap the Motorcrafts, they are usually set where they need to be.

I don't agree with getting the PCM "flashed" by the dealer. If the tech you take your car to cleared KAM, then no point in "flashing" the PCM, the only thing a dealer would due is determine if the PCM is at fault, which is unlikely, and check to see if it has the latest software update. The 94-95 cars had issues with injector drivers burning out of the PCM, but you will know if that happens.

I would listen to the PCM rather then try to say its at fault. It says rich bank1, so its probably not a misfire realted to plugs, or plug wires, as that would set off a misfire to that cylinder, not the whole bank. A leaky injector could cause the rich code, try to run a good injector cleaner through it, Marvel Mystery oil, or some Seafoam. A clogged cat will also trip that code.

[stlwagon]

Could also be a failing O2 sensor.

[davids101]

Greetings StalkerStang,

Thanks so much for your reply-very helpful :-)

Yes, my tech stated he cleaned the MAF, checked the O2 sensors and clear KAM. So I think you may be correct. And I am definitely going to change to Motorcraft plugs....since most of all my previous cars have been german I am a fan of Bosch. The tech even said Bosch works well with most german cars but not with Fords.

And I agree with you about the possible re-flashing option....it was just something the tech researched via some Ford techs as a possibility....yeah this seems like a stretch.

I have considered a leaky fuel injector...will running a cleaner through the system remedy this? When I think about a leaky injector I assume it's slowly going bad and needs to be replaced...although as you mention when injectors go bad you will stall out... But I will run a good injector cleaner... what brand do you recommend?

Also, you mentioned a clogged CAT could cause this code...any suggested remedies for this?

Thanks again for your feedback!
Cheers mate

[StalkerStang]

It depends what is causing the injector to stick. If its a light build up, then the injector cleaner might clear it out. Heavier build up is a 50/50 chance, the stronger stuff that you run through the vacuum lines like the Seafoam, or the stuff that Champion makes that you actually put inline of the fuel system and the car actually runs off of it, might clean it out.

If its a mechanical or electrical issue in the injector, then only replacing it will fix it. However what I stated with an injector driver burning out is because of the PCM, the transistor (switch) that controls the ground of the injector will burn out and cause the injector to stay on at all times. The car won't stall, but it will run very rough and push raw fuel all the way out of the tailpipes (happened to a 94 I used to have).

If you have a clogged cat, then the only way to fix it is to replace it. Or you could take the cats off, but then you have to deal with other issues, emissions, check engine light, etc.

stlwagon also mention an O2 sensor, thats possible as well. Thats another item that I would use from Ford. But if your tech has the equipment to moitor the O2 sensors, then he should see if they are switching ok, and that they aren't being "lazy" or eratic.

[JENSSEN]

I have a 2002 Mustang 3.8 V6, 5Spd that I am having a simular issue with I have had several Codes related to right bank rich or left bank rich either as a hard code or a pending code. As soon I pulled the info from the ECM I started with replacing the O2 sensors, and PCV Valve. The car has newer plugs wires and Coil pack (which packed it in last year). The car has 109,000Kms on it currently spending most of its life as a city DD car with spurts of Hiway Mileage. When I changed the PCV and reset the codes the engine light stayed off for a while and the car had a sigificant power increase. Currently the car stumbles and is way weak in lower Rpm band until the car begins to rev out and the car seems to be able to ramp up and get moving. I have suspected the Catalyst system and it feels like a plugged exhaust but also have been wondering if possibly the EGR could cause a similar fault code. Lastly the car seems less effected on power on cold start up, but returns to its issues when the engine temperature comes up to the operating range.

Would love others insight!

[JENSSEN]

Does anyone have any insight before my check engine light burns out?