Pentastar - Hard /Non Start, Bad Fuel Economy, Loss of power

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Junior Member
Jan 12, 2017
Reaction score
Ram Year
2013 Ram 1500 ST Quad 4x4
V6 3.6L Pentastar
Hey All,

Been dealing with an issue in my truck for some time.

CEL's - Air Grill Shutters (has been on for years .. ) Doesn't affect engine warm up over time in any climate summer/winter. no over heating or running below temp.

Recent, Oil Pressure Sensor P0520. It may have happened around the same time, but I don't understand how this sensor would cause a hard start , long cranking .. very long cranking .. It always starts if I turn the key off and starta gain.

There is loss of power once when accelerating between 2 and 3500 rpm. Going up hills recently around 3-4k, no acceleration and when I pushed throttle down it jumped over 6k rpm then down shifted again without gaining much. if I clear the CEL I can drive the vehicle without lights but no change in performance.

Fuel economy has lost about 20-30% - hard to gauges because it's been a hard winter but the long start has been happening since summer. into fall started suffering fuel economy.

fuel pump and added relay, no change.

I took it to a shop, they suspected fuel. It only seems to long start after the truck has been sitting a
while. I've experimented, if I roll the key forward/back before ignition and prime the fuel pump the engine starts every time without issue. they replaced the fuel pump and installed a bigger fuel pump relay - what they didn't do (not a dealership but was there previously having truck serviced by there now former journeyman Chrysler mechanic)

It's cold and winter so I'm not overly excited to go tearing into it pulling off the head to get to the sensor and replace it. Would this sensor cause the other issues? I don't want to put $$ into this if something else is wrong. The dash reads over 100PSI at all time. Oil changes, injector cleaner ran through, changed oil filter and air filter, no change.


Senior Member
Aug 17, 2018
Reaction score
Ram Year
2018,Previous 1998
3.6L,Previous 5.9L
You didn't say how many miles you have. I use the lucas fuel system cleaner at every oil change. That has worked in both my current 3.6 and my old gen 2. If it's not that, I'd suspect the cat is plugged or at least restricted.

This is the one.

The oil pressure sensor is on the oil filter housing between the cyl heads. You have to remove the upper and lower intakes to get to it.

Hope this helps!