Inconsistent Rough idle, already replaced multiple items
#11
Did u scan the comp? You may have an engine code even though your eng light isnt on--check the vacuum plugs/caps and lines very well disconnect ur tps and see if it makes a dif it is also possible you got a bad idle air control solenoid even though its new--Check the fuel pressure-shrader valve is easy to get to--what u are describing in my experience (no codes) has been a bad iac-Fuel issues usually set a lean code-and tps etc almost always set a code-
No i have not scanned the computer ill give that a try and see what comes up. thanks for the advise
#12
Did u scan the comp? You may have an engine code even though your eng light isnt on--check the vacuum plugs/caps and lines very well disconnect ur tps and see if it makes a dif it is also possible you got a bad idle air control solenoid even though its new--Check the fuel pressure-shrader valve is easy to get to--what u are describing in my experience (no codes) has been a bad iac-Fuel issues usually set a lean code-and tps etc almost always set a code-
Definitely check for any OBD codes, and check the new IAC. Take off the air hat and with the truck running look down in the port where the IAC pintle is and adjust the throttle and see if the pintle moves out and back in. It is a little stepper motor so it will make a jerky motion as it opens and closes. I replaced mine a few years ago and the new one was defective.
#13
How much of an interval between the smooth and rough idle? Is it almost a consistent offbeat jiggle while at idle and does it smooth out fine upon acceleration? Sounds a lot like issues I've been having and all things I've tried, besides 01 sensors(denso) and new TPS from dealer. Some have suggested cracked valve seats.
Have you done compression test? Make sure to follow up if you figure it out. Good luck.
Have you done compression test? Make sure to follow up if you figure it out. Good luck.
Last edited by ReadRam; 04-16-2014 at 10:42 PM.
#14
How much of an interval between the smooth and rough idle? Is it almost a consistent offbeat jiggle while at idle and does it smooth out fine upon acceleration? Sounds a lot like issues I've been having and all things I've tried, besides 01 sensors(denso) and new TPS from dealer. Some have suggested cracked valve seats.
Have you done compression test? Make sure to follow up if you figure it out. Good luck.
Have you done compression test? Make sure to follow up if you figure it out. Good luck.
#15
#16
So i was messing around again and tried to cover the butterflies to see if it would choke the engine and nothing happened. Didn't even lower rpm's. This means air is being drawn in from somewhere else right? I dont know where though the plenum is brand new along with throttle body gasket. any ideas?
#17
IAC allows air in when butterflies are closed at idle, other wise engine would stall at every stop sign. And yes it does sound like the same issue. Jiggle,shake, jitter and every couple seconds a little harder shake with a 50 to 75 rpm drop. Most people would just call it normal for magnum engine, but I've had couple other trucks to compare to. My issues were worse when it's warmer outside. The plenum repair and timing set made an improvement, but not good enough. I'm going to get a leakdown test soon. It's really annoying in stop n go traffic.
Last edited by ReadRam; 04-17-2014 at 09:31 PM.
#18
IAC allows air in when butterflies are closed at idle, other wise engine would stall at every stop sign. And yes it does sound like the same issue. Jiggle,shake, jitter and every couple seconds a little harder shake with a 50 to 75 rpm drop. Most people would just call it normal for magnum engine, but I've had couple other trucks to compare to. My issues were worse when it's warmer outside. The plenum repair and timing set made an improvement, but not good enough. I'm going to get a leakdown test soon. It's really annoying in stop n go traffic.
#19