Strange Driving Issue
Thread Starter
Racer
Joined: Apr 2010
Posts: 285
Likes: 0
From: New Prague MN
Strange Driving Issue
On our way home from dinner this evening, I noticed an odd glitch in our 86 auto coupe. Upon letting off the throttle to coast down to town speed, the RPM's did not seem to drop in relation to speed. In fact, I was able to coast through town at 1200 rpm's and roughly 25 mph for over six blocks without touching the pedal and probably could have kept going if it weren't for that pesky stop sign. I should mention at this point that my cruise control is disconnected. While applying the brakes I noticed that at around 900 rpms I would feel a rather abrupt shift. I am still fairly new to the Vette scence, but pretty much every other car I have owned drops to idle rpm's when the gas is released.
Kind of a puzzeler. Any thoughts anyone?
Kind of a puzzeler. Any thoughts anyone?
Team Owner
Joined: Oct 2000
Posts: 96,443
Likes: 9
From: Fort Knox, KY
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Check your throttle cable (TC) and throttle butterfly valve. The cable may have slipped off the valve guide, the valve may need lubricating, or the TC itself may need adjusting.
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 412
From: WV
Ever since I put in my new engine mine does the same thing. I have to hit the brakes to get the idle down as I come to a stop. If I get up to 30 mph and let off the gas the car will keep going 30mph for a long ways, but at least my idle will drop very very slowly as Im moving along..Its not the cable, I have checked that.Its not the IAC because I have replaced that also .Hope you get an answer to this because its frustrating...
Last edited by WW7; Aug 25, 2010 at 07:59 AM.
Former Vendor
Joined: Nov 2006
Posts: 2,482
Likes: 3
From: Carmichael ca
If you have access to a scantool, check the TPS and IAC numbers when this problem occurs. If the TPS stays above idle, .50-.55 volts, then the throttle is sticking. I the IAC number stays up, then ECM is sending the wrong signal to the IAC. If both numbers come down the IAC is probably sticking.
