Greetings everyone. I've given up and am reaching out to you guys, I've researched all the threads and similar problems. Apologies for the lengthiness.
My 04 RC has run great for the last 5 years, it has 71,000 miles and recently started acting up. Only mods are billy boat long tube headers, high flow cats with cut outs upstream and Hennessey cold air intake.
A month ago I was driving on the freeway and all of the sudden the truck just stopped running while on the freeway going 70 mph, gauges still had power but no rpms. I coasted off and whenever I would try and restart it, it would try and crank but not actually turn. I waited for about 15 minutes and it started again but required some throttle to keep running. Then it ran fine for a day, next day it stumbled a little while on the freeway again but recovered and seemed fine.
Then two weeks ago I was backing out of the garage, truck had been running for about 2 or 3 minutes and then it did the same thing and just stopped running. Still had gauge power and audibles. Would push the start button and nothing happened, no starter, nothing. After disconnecting the battery and reconnecting it and checking grounds it started again. I hooked up the code scanner and it said it couldn't communicate, this was while the truck was operating either engine running or off.
Kept trying and eventually the scanner did connect with the PCM and communicate, only codes it showed were O2 sensors which was expected. Cleared the codes and the truck worked fine for two days then it started doing the same thing, but in decreasing durations. Maybe 15 seconds and then die. I thought it was a ground or battery related and checked all ground points accessible and when it was running the alt was putting out 14V so no issue there. The battery is new and all grounds are clean and tight. I don't think it's a relay issue with the fuel pump or starter, I swapped those with others and still no start.
After reading through similar issues the recommended places to start was TPS, IAC, Crank Sensor and Camshaft sensor. I cleaned the IAC and replaced the TPS yesterday, did the full proper restart unplugging the thee feeds to the PCM, still nothing when I push to start. Gauges light up and sweep, but no crank. Getting out of the truck while the ignition was on all of the sudden the fuel pump started and then shut off. It hadn't been doing it's normal startup upon ignition. So, don't laugh, I rocked the truck and it would intermittently turn on and off. I actually have an audio of it if anyone is interested. I also have videos of the scanner realtime analysis when it was running. So figured it must be fuel pump related, however it doesn't make any sense that the truck won't crank just because the fuel pump may be bad. It has 3/4 tank right now.
Went to recreate the fuel pump issue and now it doesn't do that nor does it crank. It also won't connect to the PCM. So, next step recommendations? Should I bother changing the crank and cam sensors or is the PCM toast? Anyway to test to see if its the PCM?
THANK YOU!!!
My 04 RC has run great for the last 5 years, it has 71,000 miles and recently started acting up. Only mods are billy boat long tube headers, high flow cats with cut outs upstream and Hennessey cold air intake.
A month ago I was driving on the freeway and all of the sudden the truck just stopped running while on the freeway going 70 mph, gauges still had power but no rpms. I coasted off and whenever I would try and restart it, it would try and crank but not actually turn. I waited for about 15 minutes and it started again but required some throttle to keep running. Then it ran fine for a day, next day it stumbled a little while on the freeway again but recovered and seemed fine.
Then two weeks ago I was backing out of the garage, truck had been running for about 2 or 3 minutes and then it did the same thing and just stopped running. Still had gauge power and audibles. Would push the start button and nothing happened, no starter, nothing. After disconnecting the battery and reconnecting it and checking grounds it started again. I hooked up the code scanner and it said it couldn't communicate, this was while the truck was operating either engine running or off.
Kept trying and eventually the scanner did connect with the PCM and communicate, only codes it showed were O2 sensors which was expected. Cleared the codes and the truck worked fine for two days then it started doing the same thing, but in decreasing durations. Maybe 15 seconds and then die. I thought it was a ground or battery related and checked all ground points accessible and when it was running the alt was putting out 14V so no issue there. The battery is new and all grounds are clean and tight. I don't think it's a relay issue with the fuel pump or starter, I swapped those with others and still no start.
After reading through similar issues the recommended places to start was TPS, IAC, Crank Sensor and Camshaft sensor. I cleaned the IAC and replaced the TPS yesterday, did the full proper restart unplugging the thee feeds to the PCM, still nothing when I push to start. Gauges light up and sweep, but no crank. Getting out of the truck while the ignition was on all of the sudden the fuel pump started and then shut off. It hadn't been doing it's normal startup upon ignition. So, don't laugh, I rocked the truck and it would intermittently turn on and off. I actually have an audio of it if anyone is interested. I also have videos of the scanner realtime analysis when it was running. So figured it must be fuel pump related, however it doesn't make any sense that the truck won't crank just because the fuel pump may be bad. It has 3/4 tank right now.
Went to recreate the fuel pump issue and now it doesn't do that nor does it crank. It also won't connect to the PCM. So, next step recommendations? Should I bother changing the crank and cam sensors or is the PCM toast? Anyway to test to see if its the PCM?
THANK YOU!!!