It might be normal but at idle the car taps and rattles like valves are loose!

Also when cold the car idles weird up and down a few times

Also at about 35-40 MPH at half throttle car shakes like I'm running over rumble strips!

Normal?


Thanks

With 27 Views, I guess it's NOT normal???

Its certainly not normal. Take the car to the dealership and have it checked out.

Did this issue just start? How many miles are on your rig? I ask because about 1 month after I picked up mine, I went on a business trip. I was forced to get gas at some no name station in the middle of no where cause I was dangerously low. They either sold me some bad gas or it was 87 octane in the 93 pump. I got gas and headed home on my 6 hour drive. By the time I was 5 miles into my trip, the car was hesitating. Mostly from 25-45mph. In addition, the engine was tapping lightly. I actually pulled over and popped the hood at one point. I wouldn't describe the hesitation and tapping as bad as you describe, but it was present. The problem didn't stop completely until I was 1/4 way into the next tank of gas which was purchased at one of my regular stops. My dealer told me the 6.1 reduces spark if octane is < 91 which can cause these issues. Any chance you got a bad tank of gas?

Did this issue just start? How many miles are on your rig? I ask because about 1 month after I picked up mine, I went on a business trip. I was forced to get gas at some no name station in the middle of no where cause I was dangerously low. They either sold me some bad gas or it was 87 octane in the 93 pump. I got gas and headed home on my 6 hour drive. By the time I was 5 miles into my trip, the car was hesitating. Mostly from 25-45mph. In addition, the engine was tapping lightly. I actually pulled over and popped the hood at one point. I wouldn't describe the hesitation and tapping as bad as you describe, but it was present. The problem didn't stop completely until I was 1/4 way into the next tank of gas which was purchased at one of my regular stops. My dealer told me the 6.1 reduces spark if octane is < 91 which can cause these issues. Any chance you got a bad tank of gas?

I only have 800 miles on the truck! I'm not sure if it just started happening, I just noticed it. I run 93 here in VA.
Bad gas, maybe? I'll wait a tank to see what happens

SRT Engineers said that 87 octane gas is not detrimental. The computer will retard timing to compensate for lower octane levels. Just do not go drag racing!

the idling is normal...mine did that pretty harshly for the first 3000 miles, but its just the computer adjusting...dont worry about it, i had it taken to 3 different dealerships to check it out.

The Engs at the Nats were asked if 87 oct could be used, they said yes but no WOT Runs, like BLKSRT8 Said! The vibration happens sometimes just above the down shift speed to 1 st gear. The factory muffler does rattle some too, quit after I installed my MagnaFlow X Muffler. Mine never pulsated at Idle from new, probably an adjustment is needed. Go to a Dealer that will fix this and not guess or shune you away! Run a Scan on the PCM to detect what signal isn't working right. Take the Tech and Star Scanner for a ride and fasten your seatbelt and "Lay Waste"! Sorry but funning! Good Luck. I love my JGC SRT8 and would like to own another SRT8 Vehicle! Gene

Some mufflers have loose baffles. I installed the Corsa system, and the rattle disappeared.

I only have 800 miles on the truck! I'm not sure if it just started happening, I just noticed it. I run 93 here in VA.
Bad gas, maybe? I'll wait a tank to see what happens

How did you make out?

Still knocking, sounds like it's coming from the top half?

Maybe drive shaft is out of balance....just a thought.