07' Tahoe LT 4x4-Engine RPM Problem Post-Corvette Servo Install/Service

[iamdub]

No way!!! Really? That's awesome! I'd never thought outright to go looking in a jeep parts bin ealing with a Tahoe; Nice!

True story. About 3 years ago, I stopped at a friend's house for a visit but he wasn't home. In his trailer he had loaded to take to scrap, I spotted some coils that looked very much like the McGaughy 3" lowering coils I had for my Tahoe. With all the other coils he had in there, he had no idea what they came from and told me to help myself to them.

Fast forward to the weekend after Thanksgiving, I installed the McG coils to see how close to the advertised 3" they'd actually drop, and netted 2.5". Then I swapped in the mystery coils. They dropped it about 4.25" from stock height and they ride only slightly firmer than stock. Since I was going to keep them, I was then inclined to determine their origin. I sent pics and measurements of them to my buddy and he found them to be a perfect match to some he had on hand that he recently pulled from a TJ during a lift. Being they're made for a much lighter vehicle, I'm really surprised by how well they're working out.

 

[mackmcmillan]

True story. About 3 years ago, I stopped at a friend's house for a visit but he wasn't home. In his trailer he had loaded to take to scrap, I spotted some coils that looked very much like the McGaughy 3" lowering coils I had for my Tahoe. With all the other coils he had in there, he had no idea what they came from and told me to help myself to them.

Fast forward to the weekend after Thanksgiving, I installed the McG coils to see how close to the advertised 3" they'd actually drop, and netted 2.5". Then I swapped in the mystery coils. They dropped it about 4.25" from stock height and they ride only slightly firmer than stock. Since I was going to keep them, I was then inclined to determine their origin. I sent pics and measurements of them to my buddy and he found them to be a perfect match to some he had on hand that he recently pulled from a TJ during a lift. Being they're made for a much lighter vehicle, I'm really surprised by how well they're working out.

I've had a TJ as well as too many other codes and quantities for this discussion (hehe) but I guess I'll take it as a previous owner compliment that they were still making decent OEM if it's handling our rigs now. A database like that would be the coolest damn thing. Like a genealogy database or wikipedia people could help populate what works as swaps, etc. Murky waters to be sure, caveats can be a separate category. I WISH anyway.

 

[mackmcmillan]

I’m with the previous post that stated that the servo and the oil change shouldn’t have any effect on the way the engine runs. From past experiences back in the sixties GM had an issue with motor mounts breaking and when the engine torqued it would bind the accelerator and you’d have to fight it to stop and idle speed would be high which sounds a lot like what you are experiencing. The mechanic might have loosened you transmission mount and neglected to put the nut back on and that may allow the engine to torque over and cause some of the issues you are having or maybe a broken motor mount LHS probably. Check the mounts or have a different shop check the truck over.

I've been thinking about changing the mounts out anyway, honestly... And wouldn't surprise me in the least if a motor mount was indeed broken. Again, the ol' gal's still good, she's just showing her wrinkles a bit more at the moment!

 

[usnret]

A broken motor mount wouldn't affect a drive by wire engine. And yes, I am old enough to remember solid throttle linkage.

 

[OR VietVet]

A broken motor mount wouldn't affect a drive by wire engine. And yes, I am old enough to remember solid throttle linkage.

Me too.

 

[liquify33]

I’m young enough to still be driving one!

 

[mackmcmillan]

A broken motor mount wouldn't affect a drive by wire engine. And yes, I am old enough to remember solid throttle linkage.

Same on the mechanical linkages. Nothing like an SAE set of sockets and wrenches and almost nothing electronic to speak of... Good times. Even though those aren't the culprit, I have to admit it can't hurt since it's about time for all things rubber and/or "perishable" to be inspected closely anyway. Forces me to do what I should have previously. Once I'm able, it's ALL got to be gone through!

 

[mackmcmillan]

Tahoe has been dropped off and is being looked over for all things yet again to get a handle on whatever NEEDS replaced no matter the system. The battery went dead on me so I had to jump it. Go figure the revving issue seems to have been resolved (still checking into it, though for sure!) by a dead-battery-reset... So, perhaps the suggestion of a hard reset was a good one to vet out. I didn't have access to the equipment to do a plug and play reset, but so far so good and the shop knows to diagnose it (if it isn't actually resolved). I've wondered if I had a bad chassis ground wire. Seems the negative battery cable is shot instead. I'll try to keep this updated as answers become available in case it should help someone else later on, etc. Sorry for the post and vanish act; Most of it is beyond my control.

 

[iamdub]

Sorry for the post and vanish act; Most of it is beyond my control.

No worries! We can only be appreciative that you're keeping us updated on both the good and bad so others may learn.

 

[mackmcmillan]

No worries! We can only be appreciative that you're keeping us updated on both the good and bad so others may learn.

Many thanks!