[VicTemon]

i have a 1997 v6 and ive had a couple people try to help me but i still cant get to the bottom of it. p0175 is a bank 2 system rich/lean. like in my previous postings, i have replaced alot. cleaned throttle body, did lower and upper intake gaskets, cleaned injectors, and replaced harness wires, replaced downstream o2s(because when i had a livewire ran they were reading low), replaced egr pump, all vaccum lines exept the ones on the DPFE, fuel pump is working and good pressure, fuel filter, charcoal canister, purge valve(because it blew that code in middle of all this), new wires,plugs,and coil pack amongst other things. car is idling rough and i gained some power back when i did the lower gaskets but still should have more power with what i have into it. driving me nuts! can someone please give me some insight? id give my left nut to figure this one out at this point!

[shinerstang]

What is your fuel rail pressure? Have you missed any vacuum hoses? Have you sprayed carb cleaner around the motor with it running to find any vacuum leaks?

[VicTemon]

to be honest, i dont remember what the pressure was ill have to have it checked again. i do remember that it checked out ok according to the mechanic that did the diagnostics. like i said, the only hose i didnt check or replace were the ones running to the dpfe. i also replaced the upper,lower,egr,and throttle body gaskets all in one shot just this week. and yes i double checked for leaks with wd-40 and carb cleaner. do you have any more suggestions for the p0175 code? thanks for the reply back man. i am new to this so i do appreciate anyone thats willing to help me out.- Vic Temon

[shinerstang]

If it were me, I would start pulling plugs on the driver's side to see if any one cylinder is running lean/rich. It could be a bad injector. If it is, I have some left over from an old motor. Did you use the motorcraft wires or cheap generics? Generics do not have the proper connectors for the coilpack.

What about your upstream sensors? They are the most important ones......

Also clean your mass air sensor with the proper cleaner......

[VicTemon]

yeh i got the real deal wires but those arent the ones im talking about. im talking about the harnesses that plug to the injectors. i cracked one so i just replaced them all to rule that out. ive already cleaned my maf and the whole carb cleaner deal. according to the computer, my upstreams ore reading ok. when i got in my car yesterday and today the idle was soo rough that i thought it was going to stall but as the idle gets worse, i dont seem to be losing any more power throughout driving range. the only wierd thing is that in neutral when i slowly rev up the rpms when it hits 2,000-2,500 rpms, it almost sounds like its stamering. almost like its missing on a cylinder. not quite harmonic you know. you can feel it. i have to figure this out soon. not even the two shops i brought it to could tell me what was wrong. i NEVER bring my car to a shop and now i remember why i do all this stuff myself.

[stangluver111]

Did you happen to remove the cats on your mustang or are they bad, well atleast half of them? We had a guy come into our shop who did not have cats and was getting 4 codes. 2 were a general obd2 emissions code, the other 2 were this for both banks 1 and 2. We put new cats on and sensors and it fixed all 4 problems and the CEL went away. Whether it just happened to be random that the p0175 code went away or that the cats actually fixed it, you may want to check that out. Oh and one more thing. If it is a vacuum problem, we found twice where there are two frail lines by where the intake hose and the tb meet that are red and green that can sometimes brake when you do tb cleaning. One going to the egr and i forget at the moment where the other one went and we replaced these and they seemed to fix the erratic idle problem.

[shinerstang]

Originally Posted by VicTemon

yeh i got the real deal wires but those arent the ones im talking about. im talking about the harnesses that plug to the injectors. i cracked one so i just replaced them all to rule that out. ive already cleaned my maf and the whole carb cleaner deal. according to the computer, my upstreams ore reading ok. when i got in my car yesterday and today the idle was soo rough that i thought it was going to stall but as the idle gets worse, i dont seem to be losing any more power throughout driving range. the only wierd thing is that in neutral when i slowly rev up the rpms when it hits 2,000-2,500 rpms, it almost sounds like its stamering. almost like its missing on a cylinder. not quite harmonic you know. you can feel it. i have to figure this out soon. not even the two shops i brought it to could tell me what was wrong. i NEVER bring my car to a shop and now i remember why i do all this stuff myself.

I don't know any great V6 guys in Michigan either. Too bad you're so far away......

[green4money00]

did you check compression and the resistance on all you injectors?
an exhaust leak can cause the 02 sensors to read lean as well... it usually has to be a pretty large leak tho

[VicTemon]

thanks for the replies everybody. my 02 sensors are still reading real low and it seems to be idling even worse now. definately not getting better. when i just did my lower intake gaskets i tested the injectors with a 12 volt source and they seemed to all click. could they still be bad? i cleaned them all out as good as i could. can that cause a very low reading for the o2 sensors? when i first developed this problem the guy told me my sensors were bad or the cats were punched out by the exhaust shop that did my cat back system last summer. if he did punch them out, wouldnt it have instantly ran bad? its been steadily progressive. by the way i do have all four cats still on. its idling soo bad it feels like its gonna stall. is there a way i can test the cats without replacing them. ive already put too much money in this. if they are bad, can anyone tell me where i can get that section for less than $500? or can i go with two high flows without causing problems? help me guys, your my only hope. i was really hoping i could find somebody that had this specific code and knew exactly what it was. oh.....when i unplugged my maf sensor, it idled better and go figure when i turn on my a/c(what the hell?) but when i drove it with it unplugged, it ran bad. does that mean anything? i tested the resistance according to the haynes and it tested fine. help?