RPM drop '11 - Chevy Traverse Forum: Chevrolet Traverse Forum
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post #1 of 24 (permalink) Old 01-21-2017, 05:36 PM Thread Starter
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RPM drop '11

So I've spent hours and hours doing research on here before having to ask the questions (rare, I know ).

My '11 LTZ with 125k recently started doing RPM drops.

They are pretty often, whether I'm in or out of cruise control. It occurs at city or highway speeds...even on my 25 mph residential street. It's more noticeable uphill (speed stays steady).

Sometimes it's just a quick drop, other times it feels like I'm going over a rumble strip.

I performed the obvious maintenance after reading the forums: Transmission fluid drain and fill, purge valve replaced, coil packs all tested ok and new spark plugs were installed.

After the new plugs it seemed to drive normally for the first 5 miles, then the RPM drops slowly came back to their recent level after another 10 miles.

I've also noticed a drop in MPG if that helps. I was at 19.5 avg, now down to 18.

The RPM fluctuation is usually around the 200-300 range.

Any ideas?
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post #2 of 24 (permalink) Old 01-21-2017, 05:59 PM
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Re: RPM drop '11

Just a wild ass guess, but I'm thinking fuel pump or fuel filter for starters. No codes on DIC?

2015 2LT
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post #3 of 24 (permalink) Old 01-21-2017, 06:10 PM Thread Starter
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Re: RPM drop '11

Quote:
Originally Posted by Kemosabe
Just a wild ass guess, but I'm thinking fuel pump or fuel filter for starters. No codes on DIC?
No codes, no CEL.

P0496 came up for the Purge Valve, but has cleared since replacing.
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post #4 of 24 (permalink) Old 01-21-2017, 08:23 PM
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Re: RPM drop '11

I'm taking a wild guess, but maybe the cam position sensor?

My 1996 Eagle Vision sensor went bad. I'd be driving along and suddenly the tach would drop, then it would pick back up again in a second or so. This happened a few times over a couple days. Then it died completely and I left it at the side of the road. Came back a few hours later and it started right up. Drove it right to a mechanic and he changed the sensor. That fixed it.

2011 2LT FWD replaced by 2017 2LT AWD
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post #5 of 24 (permalink) Old 01-21-2017, 08:50 PM
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Re: RPM drop '11

How did the coil packs test ok? If all you did is unplug one at a time at "idle" that wont do it for a test. By what you said it looks like you have a higher rpm problem. I'm going to vote for a coil pack dropping out with not enough volts to keep up with the higher RPM speeds... Higher RPM less time for the pack to get recharged.
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post #6 of 24 (permalink) Old 01-21-2017, 08:58 PM
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Re: RPM drop '11

like this?

https://www.youtube.com/watch?v=_g7fdzLPZ9M


2010 FWD LT1-Gold Mist Metallic- seats 8.
Build Date- July 31, 2009-2nd day of Spring Hill 2010 production.
2013 Equinox 3.6L - 60,000
2010 Traverse 3.6L- 127,000
2003 Trailblazer 4.2L- 180,000
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post #7 of 24 (permalink) Old 01-21-2017, 09:31 PM Thread Starter
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Re: RPM drop '11

Quote:
Originally Posted by rbarrios
That looks a tad worse than my issue, but very similar. That's a pretty large jump. Mine is 300 max.
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post #8 of 24 (permalink) Old 01-21-2017, 09:32 PM Thread Starter
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Re: RPM drop '11

Quote:
Originally Posted by MrSteve
How did the coil packs test ok? If all you did is unplug one at a time at "idle" that wont do it for a test. By what you said it looks like you have a higher rpm problem. I'm going to vote for a coil pack dropping out with not enough volts to keep up with the higher RPM speeds... Higher RPM less time for the pack to get recharged.
They tested ok because they were removed from another motor with no misfires/issues. More of an assumption. All six were swapped and the issue persists.
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post #9 of 24 (permalink) Old 01-23-2017, 07:45 AM
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Re: RPM drop '11

Have you tried doing a throttle body cleaning? A dirty throttle bore/plate will seal off the air going into the engine and cause a lower idle. This will cause problems mainly off throttle.

2012 Traverse LT2
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post #10 of 24 (permalink) Old 01-23-2017, 11:21 AM
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Re: RPM drop '11

Quote:
Originally Posted by rbarrios
This video seems to show the RPM's going UP. OP said his was dropping. Not sure this is the same issue??

2011 2LT FWD replaced by 2017 2LT AWD
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