Hello this is my first posting here because I cant seem to find an answer on the internet to my issue.

1) I recently bought a 2005 dodge 1500 quad cab 4x4 with a 4.7l at auction. I noticed on the way home that the truck will not hold cruise setting on the highway. It accelerates fine shifts smooth drops into OD (about 1850rpm at 65 mph) I set the cruise and it will hold if for a few seconds then the speedo starts to drop and I can feel the accelerator going further and further to the floor till it up shifts to 3000 to speed back up then back down to OD and it will bounce back and forth from there. If I just use my foot I can maintain 65mph in OD all day long but I am getting tired of this. The only time it will stay in OD with cruise is with a tailwind. I have checked fluid that is it. Any ideas??

2) Gas mileage is HORRIBLE!!! 12-13mph Is this normal with a 4.7l engine. My hemi of the same year got 17 all day long. Anything I need to be looking at here to improve this.

Thanks for any information

 

https://dodgeforum.com/forum/dodge-r...s-section.html

 

This issue has been covered a few times on other threads.. do a quick search.

 

Did do a search cant find the symptoms I am experiencing. Do you have a link for said threads??

 

Sounds like it might be a vacuum leak. Never had this issue but hopefully someone can chime in and maybe give you some links. The search doesn't always work great if you're not using the 'magic words' or words that are long enough for that matter. Anyway the MPG sure seems low if we're stickly talking highway.

 

I have to agree with the vacuum leak theory, especially if the 2005 cruise control is cable driven.

 

Changed plugs and all coils and took it for a quick test drive and it seems a little better. Mileage computer still reading low. Done 2 seafoams through the gas tank. Going to get the trans flushed and serviced this week. Running out of ideas.

 

my 03 ram 4.7 avgs 11.5-12.5 city driving and that is hand computed

 

Speed sensor?

 

Its got to be a vacuum leak.... I know when its not plugged in then OD does not work at all. So it sounds like it builds vacuum but as soon as the RPMs go down it bleeds of and does not build it fast enough... then drops it until the vacuum builds up enough to engage it again.

Go find your leak!

SPEED SAFE, AIR RAM