hey guys I have a 03 touring AT with 82xxx miles i just recently added a motor dyne 5/16 inch copper iso thermal spacer. i also have a split in my exhaust pipe right before my muffler.

so the car started doing this thing right after i did an ECU reflash. idling in neutral, park and reverse has no issues. when i idle in drive however the car rumbles. but only in low rpms. as soon as i rev up to about 2k rpm the noise and feel goes away and there is no abnormal feeling. the car rumbles so much that you can feel it on the body of the car if you hold your hand on it. you can also feel it in the brake petal rumbling. there is no check engine light. I've driven my car like 5 times since i did the reflash drove in total probably about 100 miles. out of the 5 drives it only rumbled 3 or 4 times. also about 2 weeks before the reflash when the car get hot. and not just hot but normally when driven for more then 30 miles i get this smell inside the car which is almost like burning rubber as if i had spun my tires. but it is very subtle.

i have no idea whats going on I've been reading for hours and have found nothing that matches this. at first i thought it was just my exhaust pipe vibrating against itself. but i don't think thats it. maybe its misfiring? but why no CEL?

any thoughts would be greatly appreciated

 

Video?

 

You can just hardly hear it in the background of this video when I'm in drive

 

could this 'Rumble' be the engine sputtering or missing?

Having the rubber gasket pinched after installing the upper plenum makes the car kind of stumble as the Air/fuel ratio get messed up.

I was UBER careful when I did mine but still had it happen. I would take the upper plenum off and double check.

Just a thought.....gl

 

Make sure car isn't running to lean. I did a reflash of previous Z after mods that gave a smell and car was running to lean. All was fine with proper tune.

 

vacuum leak. check your spacer install...

 

Thanks guys. I'm stupid. The plenum was rubbing on the strut bar -___-

 

This is what I was going to say. I had this happen after my spacer install as well, didn't think about adjusting the strut bar, glad you figures it out soon tho, it can make some nasty scratches in your plenum