Air filter swap, MPG sucks really bad.

[Wambliokiye]

Ok! I changed out my OEM filter for a new cone filter. Didnt put the tube in still has the factory crap, i just put the filter on! What in the @#$&%*@%#*$*@%#*$?#%@ did my MPG go???? like the MPG was crap before at 12-14 mpg now the phucker reads 8.6 mpg. I filled it up cleared the average jumped on the high way , high way before filter swap was around 14-16. No racing no quick acceleration or fast stops with no Cruz control ....8 MPG! WTF? In town its at 2.2- 3.4. Before the high way was way more than 8 and city way more than 3!?!?!?! I am thinking about new fuel filter uhhh IDK! I am just so pissed right now with my devorce and the cash thats sucking outta me and now Nali wants to start acting up and requiring more money what is not a problem at all but the timing really sucks. If i put the old filter back in and the MPG has no change what do i look for????? And yeah if it goes back to normal its sonething to do with the filter alone on stock tubes, right?

 

[RST Dana]

Any chance you filled it up with E85?

 

[swathdiver]

Check for a vacuum leak, anything loose or not properly put back together between the air filter and throttle body/intake. Use your Tech2 and check the Long Term Fuel Trims and the alcohol content of the fuel.

 

[kbuskill]

470 HP isn't free you know

Seriously though... it probably has more to do with the HOT underhood air your engine is now ingesting.

Hot air should make it run more lean but it also makes less power and your truck still weighs the same so it would be working harder.

 

[iamdub]

Any chance you may have damaged the MAF sensor? SES light on?

 

[drakon543]

getting hot engine air temp yes but effecting it that much no. not unless he is driving around with the engine literally on fire. im leaning towards the vacuum leak or possible damaged or dirty maf sensor. on most vehicles the iat difference between stock, short ram, or an actual cai while the vehicle is in motion is small. enough to nudge your power numbers yes but generally not even noticable. also you didnt mention much besides you put a cone filter on. where did you get it and what brand. some cheap cone filters tend to come over oiled and will throw off the maf.

 

[swathdiver]

Too much oil on the filter could've messed up the MAF too.

 

[Tonyrodz]

Too much oil on the filter could've messed up the MAF too.

Wouldn't he get a code/check engine light with that?

 

[swathdiver]

Wouldn't he get a code/check engine light with that?

I would think so but maybe it was just enough to skew the numbers? Hard to say without readings.

 

[iamdub]

Wouldn't he get a code/check engine light with that?

Not necessarily. If the MAF is reporting to the PCM within it's parameters, the PCM is just gonna respond to what it's being told by the MAF based on how it is programmed to do so. The PCM has no way of telling if the MAF is "lying" or not. The same goes for the other sensors which is why someone competent with a scan tool and knowledgeable of the vehicle they're working on can see that a sensor's reported figures are excessively low or high. If the PCM sees that the MAF is reporting outside of those parameters, then it knows there is a problem and THEN it'll throw a code. The MAF may be reporting inaccurately but still within it's parameters.

There is a bit of "checks and balances", though. The MAF says X amount of air is passing through it so the PCM should expect X amount of manifold pressure at X throttle angle at X RPM. It will adjust the fueling accordingly and the upstream O2 sensors report the outcome. If the "X fuel in" (fuel includes air) doesn't result in the expected "X exhaust out" (within a range), then the PCM sees a problem and will throw a code. In this case, it'll likely be an O2 sensor code indicating a rich or lean exhaust. This doesn't necessarily mean the sensor is bad. It just means the exhaust is either rich or lean and it is up to the mechanic to find out why. I.E. Is it a failed injector or the injector pulse made too long or short by the PCM responding to inaccurate data being reported by another sensor?