POISND U

My SES light came on yesterday and I haven't had a chance to get it read yet. I just wanted to know, in all of your guy's vast experience, what are some of the most COMMON reasons and what are some of the worst you've heard of?

8banger

Most common at the shop would have to be po440 and po442 evap leaks,,,,,next would have to be po420 cat efficiency code...usually a weak convertor.....and the worst ?maybe po171 or po174 lean codes ,,which could beseveral things ,,and time consuming sometimes to find.....these last 2 weeks,,I've had 4 merc cougars(mazda 2.5 V-6)for these codes,,,the upper plenum and lower intake gaskets sucking vaccum because of the cold temps.Those plastic gaskets suckkk!!!!!.....replaced Gm's ,fords, (all models) using plastic gaskets and today a Mazda MPV with the same 2.5 V-6 found in the cougar...But yeah,,lean codes or rich codes tend to be the most troublesome to find sometimes....for me...

and another common code po300 random misfire...gm shows number of misfires oneach cylinder and the fords,,I can go into global obd II to find them instead of waiting for a particular cylinder to show,,po304 etc.....

chris01gt

Yeah I could'nt get rid of that damn light in my cougar (intake problem), maybe it was all the duct tape holding it together. [8D]

8banger

LOL....common complaint on these is,,,high idle,,fluctuating idle cold ,Stalling cold,but gets better or perfectwhen warm,,,and po171 or 174,,,and maybe a misfirs or 2 ....yeah I've had trouble getting the gaskets,local partshouses are runnin out....LOL

laserred38

mine just came on the other day too...i left the car at home and my dad took it to our shop for me to have the code read (i'm in college and don't live at home, but i do come home every weekend to work so no negative comments please )...he didn't tell me the exact code but it was "gross vacuum leak" or something like that...the shop said it is usually the gas cap not on all the way....but i checked that when it first came on and it was tight...either way they reset the computer and it hasn't come back on yet (crossing fingers) so go outside and check your gascap!

8banger

that prob be a po455 evap gross leak .....and usually the gas cap gone.LOL.....

Fizzics Boy

a common one would have to be p0420 and p0430, those are mine, but i dont have an cats . i dont believe in those things.

beastzilla02

if ur running rich can ur car be slower ?

POISND U

It came on immediately after I got gas, but I'm sure the cap was on right because I used to sell Fords and I told all my customers to be extra careful about that.. I'm hoping that's all it was....

Fizzics Boy

go to autozone, theyll read the codes for free