Sportony
Junior Member
Hello. Newbie to forum here. Hoping for some input from those with greater experience on a mystery that is really vexing me. I am truly stumped with this one. Have a 2003 5.7 hemi automatic, quad cab. 115 K miles on remanufactured engine that was replaced in 2012 due to infamous hemi tick. (230 K on body total). The truck has been meticulously maintained, and was running great - completely normal, without any indication of any problems or issues whatsoever a month ago.
I was driving truck and pulled into the driveway (again without issues). Couple hours later, had to get back in to drive elsewhere. Suddenly after initial startup, it started to idle very wildly. Check engine light and infamous red lightning bolt came on the dashboard. It would start off idling at 3500 RPM for about 2-3 seconds, then would calm down and idle would fluctuate rhythmically between 700 and 1500 RPM. No ticking or pinging, but strong smell of gasoline. Would limp forward if put in drive and would idle erratically, but without shutting off. Now it only runs for about 5-8 seconds with same symptoms, then spits / sputters / cough and then shut off. If you try to put it in drive it cuts out. I have hooked up OBD scanner multiple times with No Error Codes !! (it works with my other vechicles, so doubtful it's a bad scanner).
I have studied youtube videos without much luck on the problem. I'm mechanically inclined with several engine rebuilds under my belt, but all have been older 50s / 60s mopars.
Have replaced or checked the following on the truck (all new or recent replacement)
1. Throttle body
2. PVC valve
3. MAP Sensor
4. Crank sensor
5. Cam sensor
6. new Coil packs
7. New spark plugs
8. Rebuilt alternator 18K miles ago (that still works fine - tested and normal)
9. new battery.
10. Tested fuel pump - working well (tested, works fine, delivers consistent 40 psi with fuel gauge attached)
11. Timing chain and tensioners normal
12. Fuses checked; all appear normal
13. TB sensor in the airbox is routinely cleaned
14. Checked for shorts or cracks / breaks in wiring harness - I could not identify any
Have not tested the APPS (not sure how) nor can I get a new one since it's now a non-production item.
Have not changed O2 sensor as I figured this would produce a code if they were faulty. I do have to replace the harmonic balancer due to the seal cracking and breaking. After removal, I took down the front cover and inspected the timing chain. I thought it may have jumped time, but timing chain and tensioners appear normal after takedown and inspection.
Do I need to do a leakdown or compression test ? I thought red lightning bolt meant some error in electrical or spark. Seems so odd that one drive cycle it runs completely normal, and then the following cycle, without any indication, it runs like crap.
Any help or guidance would be SINCERELY APPRECIATED ...........
I was driving truck and pulled into the driveway (again without issues). Couple hours later, had to get back in to drive elsewhere. Suddenly after initial startup, it started to idle very wildly. Check engine light and infamous red lightning bolt came on the dashboard. It would start off idling at 3500 RPM for about 2-3 seconds, then would calm down and idle would fluctuate rhythmically between 700 and 1500 RPM. No ticking or pinging, but strong smell of gasoline. Would limp forward if put in drive and would idle erratically, but without shutting off. Now it only runs for about 5-8 seconds with same symptoms, then spits / sputters / cough and then shut off. If you try to put it in drive it cuts out. I have hooked up OBD scanner multiple times with No Error Codes !! (it works with my other vechicles, so doubtful it's a bad scanner).
I have studied youtube videos without much luck on the problem. I'm mechanically inclined with several engine rebuilds under my belt, but all have been older 50s / 60s mopars.
Have replaced or checked the following on the truck (all new or recent replacement)
1. Throttle body
2. PVC valve
3. MAP Sensor
4. Crank sensor
5. Cam sensor
6. new Coil packs
7. New spark plugs
8. Rebuilt alternator 18K miles ago (that still works fine - tested and normal)
9. new battery.
10. Tested fuel pump - working well (tested, works fine, delivers consistent 40 psi with fuel gauge attached)
11. Timing chain and tensioners normal
12. Fuses checked; all appear normal
13. TB sensor in the airbox is routinely cleaned
14. Checked for shorts or cracks / breaks in wiring harness - I could not identify any
Have not tested the APPS (not sure how) nor can I get a new one since it's now a non-production item.
Have not changed O2 sensor as I figured this would produce a code if they were faulty. I do have to replace the harmonic balancer due to the seal cracking and breaking. After removal, I took down the front cover and inspected the timing chain. I thought it may have jumped time, but timing chain and tensioners appear normal after takedown and inspection.
Do I need to do a leakdown or compression test ? I thought red lightning bolt meant some error in electrical or spark. Seems so odd that one drive cycle it runs completely normal, and then the following cycle, without any indication, it runs like crap.
Any help or guidance would be SINCERELY APPRECIATED ...........
Last edited:
