Is my truck getting normal MPG Can I change the gears?
Banned Goober Smoocher
Joined: Jun 2010
Posts: 8,916
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You guys have to remember that the 5.2 (318) and 5.9 (360) Magnum engines were designed in the late '60s when gas mileage was an afterthought. Yes these engines received a few modern updates (aluminum heads, EFI, etc.) over the years but are down at the core 30+ year old designs when they were discontinued in '02/'03.
That said, my 2nd Gen RCSB 5.9 4x4, lifted with 35" tires and only basically a re-done exhaust for mods got about 9 mpg around town and about 12 on the interstate, so I'd say you have an issue or two going on. Could be just a matter of needing a tune-up, but I'd still check the plenum gasket...
That said, my 2nd Gen RCSB 5.9 4x4, lifted with 35" tires and only basically a re-done exhaust for mods got about 9 mpg around town and about 12 on the interstate, so I'd say you have an issue or two going on. Could be just a matter of needing a tune-up, but I'd still check the plenum gasket...
As was said above, do the plenum, and tune up stuffs. That will get you into the low teens. I have done this along with a new cat and I get 13 at 75mph with 33 in tires.
Registered User
Joined: Jul 2013
Posts: 12
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Im confused as well...to me that would create a vacume leak causing a lean mix not a rich one not to mention teribal Ideling as well as hesitant accelerations from stops or otherwise, non of which the OP mentioned. But like I said I don't know Dodges.
Im curious to learn the outcome.
Last edited by Stillraining; Jul 29, 2013 at 05:25 PM.
Banned Goober Smoocher
Joined: Jun 2010
Posts: 8,916
Likes: 1
Im confused as well...to me that would create a vacume leak causing a lean mix not a rich one not to mention teribal Ideling as well as hesitant accelerations from stops or otherwise, non of which the OP mentioned. But like I said I don't know Dodges.
Im curious to learn the outcome.
Im curious to learn the outcome.
A blown plenum causes a vacuum leak that causes a deficit of power, you try and compensate by opening the throttle more, the PCM sees this and increases the amount of fuel used.
Read this:
https://dodgeforum.com/forum/2nd-gen...um-thread.html
All 5.9 V8 owners should really be referred to the 2nd gen Ram section as it has THE most activity and the most knowledge on the forum in the regard with the Magnum engines.
Record Breaker
Joined: Apr 2013
Posts: 1,815
Likes: 56
From: Alberta
if the vehicle used a maf to measure air volume a vacuum leak would lean out the fuel mixture but as it uses speed density fuel metering, any increase in the map is seen as increased engine load....like opening the throttle plate
Last edited by primem; Jul 30, 2013 at 08:32 AM.