Not going above 3,500 rpm's and hard to start when it gets hot

2003 DODGE RAM
215,000 MILES • 4.7L • V8
Avatar
STEVEN121261
  • MEMBER
  • 3 POSTS
Put cam sensor in crank sensor in put. Put MAP sensor in putiat sensor in and when it is hot it will not start.
Sep 6, 2018 at 7:44 PM
Advertisement
Avatar
HARRY P
  • CERTIFIED EXPERT
  • 2,292 POSTS
I would bet on a weak fuel pump with that many miles on it. Stop by the local parts shop and borrow a fuel pressure test set from their loan-a-tool program. Then follow the instructions that are in the attached image.

Also, here is our more general how-to guide on testing fuel pressure: https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Check the pressure and let us know what you find. We will go from there.
Sep 7, 2018 at 5:23 AM
Avatar
STEVEN121261
  • MEMBER
  • 3 POSTS
Thank you, but when it is cold it runs great when it gets hot it is hard to start.
Sep 7, 2018 at 8:31 AM
Advertisement
Avatar
HARRY P
  • CERTIFIED EXPERT
  • 2,292 POSTS
I understand that. Sometimes a bad pump will be okay until it warms up a bit. Then the pressure drops a bit and it runs really bad, if it runs at all. My dad's 1995 Dodge Dakota did that. When it was cold, it put out something like 40 psi. Once it warmed up, the pressure output would drop to about 22 psi, and the truck would not do much more than idle.

One question though, is the service engine light on?
Sep 8, 2018 at 3:37 AM
Avatar
STEVEN121261
  • MEMBER
  • 3 POSTS
I am getting a p0116 and a po558 and a po339 and a po594 when it is hot.
Sep 8, 2018 at 6:47 AM
Avatar
HARRY P
  • CERTIFIED EXPERT
  • 2,292 POSTS
P0116 - Engine coolant temp sensor circuit range/performance - could cause your running issue
P0558 - Brake booster pressure sensor circuit high - likely not related.
P0339 - Crankshaft position sensor "A" intermittent - can cause all sorts of running issues
P0594 - Cruise control servo circuit control open - likely not related

The images below address testing the coolant temperature sensor. I will address the CPS in the next post.
Sep 10, 2018 at 4:02 AM
Avatar
HARRY P
  • CERTIFIED EXPERT
  • 2,292 POSTS
Here is the information on testing the CPS:
Sep 10, 2018 at 4:08 AM