Bad MPG

Pickles

Pickles

Reads too much
Joined
Jun 25, 2010
Messages
126
Lately I've been getting 15mpg, with fuel economy tune or not, I have an exhaust as modifications go, new air filter, fuel filter, oil change, I get code P2121 sometimes on the highway, I was told it was a combo of a bad FCA and "shift flarring" is this true?
 
Thanks, and I went from 21.6 to 15.3 avg so something isn't right
 
So look up your code in the Sticky thread at the top of this forum that you COMPLETELY overlooked before. There may be a hint there...here's another...it has NOTHING to do with what you were told.
 
Pickles said:
Lately I've been getting 15mpg, with fuel economy tune or not, I have an exhaust as modifications go, new air filter, fuel filter, oil change, I get code P2121 sometimes on the highway, I was told it was a combo of a bad FCA and "shift flarring" is this true?
Click to expand...

2121

i know it well, look up my threads fwiw.. has to do with apps..

good luck gettin rid of that sumvabuck
 
UNBROKEN said:
So look up your code in the Sticky thread at the top of this forum that you COMPLETELY overlooked before. There may be a hint there...here's another...it has NOTHING to do with what you were told.
Click to expand...

I looked up 2121, and searched it too. Lead me to FCA
 
P2121 Pedal Position Sensor 1 Performance / Rationality, I know that is what I read, when I googled 2121 I saw FCA along with being told that in person that is why I asked.
 
Pickles said:
P2121 Pedal Position Sensor 1 Performance / Rationality, I know that is what I read, when I googled 2121 I saw FCA along with being told that in person that is why I asked.
Click to expand...
So the code is APPS, but you are gonna believe what an idiot told you, because another idiot on Google said it?:bang
 
My truck doesn't smoke on idle or lope and stats up fine, I don't have a rail pressure gauge to check that which I should get one soon. I have stock injectors. As for APPS and TPS there a link or thread on how to test these? I searched for it but only found other people asking the same.
 
Pickles said:
My truck doesn't smoke on idle or lope and stats up fine, I don't have a rail pressure gauge to check that which I should get one soon. I have stock injectors. As for APPS and TPS there a link or thread on how to test these? I searched for it but only found other people asking the same.
Click to expand...

go along with your title on here

reads too much, apply that one on here, google is one of the worst sources for accurate info on our trucks, any person can put info on anything on the net, much like a book, if you dont have a reputable source, wth are you doing?? your apps..... if you wanna test it, it needs to be hooked to a computer to do so, there is a reset thread on here, there is also ALOT of info on my threads started with this truck

2121 can be many many things that cause it, trust me, just check all that ive done and apply it to get rid of it.. start with the simple, and work from there... also you gotta think P2121 may not be the same reading on other motors as it is for our cummins trucks...

fuel mileage is also NEVER accurate on the overhead, mine reads i get 10.8, when in reality i get 14 or so city, and 19-20 highway... hand calculate it, and that will surprise you...
 
Last edited:
My mpg readings are hand calculated and that was a mix of hwy/city, I only looked for cummins when I googled 2121 but in the last 2 days I noticed what you just said is very true, I don't find much on google, and I do read a lot too lol, anyways I'm having my trans done by Tim Barber next month, I'm going to have him go through anything he can while my truck is there if I don't fix anything before hand.
 
You must log in or register to reply here.
Top