10 mpg problem

[Islanderppc]

2012 JK sport. Says 10 mpg. 16-17 usually. Also I have loss of power a bit when accelerating. Maybe 20-30% less power. Runs smooth.

I have a p0520 code. Oil pressure sensor malfunction.
Shouldn't be related.

O2 sensor maybe? Cat convertor? I took out the air filter..which was dirty..but no difference.

Going to check vacumn lines now. Unplug tps, map sensors one at a time.

Any suggestions appreciated.

 

[Jeepergeo]

My first guess would be a vacuum leak.

 

[mark sr]

How many miles on the jeep? It does kind of sound like a plugged cat but that usually happens well after 150k.

 

[JPNinPA]

Bigger tires? Different gears? Speedo corrected?

A VAC leak will cause higher idle.

I had a CAT replaced under warranty cause it fell apart from overheating. Also had a slow O2 sensor. It decreased the mpg but not to 10mpg more like 14-15 mpg.

Id start with checking the battery voltage and connections. Bad battery or grounds can cause big issues.
Check your fuel pressure and do a leak test. Pressure key off. Key on, idling at 750rpm, and running at 3000rpm. Shut the engine down and watch how long it takes to loose any pressure. It should hold steady for a long time.

What kind brand and model spark plugs are you using? Have you checked them? What did they look like?

Then clean the TB and IAC . Be sure the TPS is working. Bad TPS will have dead spots where when pedal is pressed no change in rpm occurs.

Any blue smoke out of the exhaust? Loss of oil? Oil smell like gasoline?



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[TerryMason]

sounds like JPNinPA is giving out quite the homework assignment

 

[JPNinPA]

sounds like JPNinPA is giving out quite the homework assignment

Sorry did I reach my quota?


BTW to the OP does your check engine light blink continuously? Limp mode will kill mpg and power.
And 2013 and 14 had issues with oil pressure sending units going bad early.
Regards,
JPNinPA

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[Islanderppc]

BTW to the OP does your check engine light blink continuously? Limp mode will kill mpg and power.
And 2013 and 14 had issues with oil pressure sending units going bad early.
Regards,
JPNinPA


No the engine light doesn't flash. Turns out it was the air filter after all.
Dropped my mileage to 10 mpg...took it out..drove it around...went up to 16.7.

Could be the TPS needs cleaning or replacement the bad spots seems to occurring.

Thanks

 

[JPNinPA]

Ok I change air filters. Or clean the aem one I have every 2 oil changes unless they look dirty. Once I had an issue with a mouse making a nest in my one car's air box and the bird seed the mouse stored up there clogged the filter enough to stall the engine.

TPS can be blown out with some air. I would start by fully opening and closing the TB valve by hand about 50 times. Then see if it is better. Sometimes a little dirt can get in and cause issues. If that doesn't fix it look to buying a new TPS. And Buy OEM only. Others are bad out of the box or do not last.


Regards,
JPNinPA

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