Fixed high idle miss stutter off idle hesitation etc

[Curtis]

So been chasing this problem for months
Cold runs fine until I cut it off and after a heat soaking car goes nuts

High idle
Hunting idle
Check engine lights blinking on and off
Off idle hesitation or stalling
Bucking
Missing
Stuttering
Off throttle miss during decel
Miss or skip when applying gas after coasting in any gear
Gas mileage sucks

So how I figured this out
Luck
pulled into a parking lot hard and miss disappeared so new it was something loose.... so a week or so later went to an auto parts store to check alternator...
When I restarted it idle jumped to 2k and climbed to 3k.
So I tapped the tps with a Allen wrench and instantly it dropped to a perfect stable 750 and cel went off....
Went home set the tps and it was off a hair but after driving the next day when cold same old deal after second start up
So few days later when hot I started playing with tps plug when idle went nuts
and finally got it to stop. Realized the pins in the plug after 30 years of vibration had flatted out and are loosing connection. The pins should be bulging in the middle...the way mine is routed wires bend 90 to drivers side for an inch or so then down then a 45 under intake so every movement cause the lever arm to pull at wires.

So I de-pinned plug spread open all 3 and reinstalled and after like 4 times got all 3 wires to make full tight contact and not unpin themselves after that folded wires over to plug and zip tied to eliminate this from happening again or wires having any vibration....

So hope this helps....

[DRM500RUBYZR-1]

Great catch!!!
Oftentimes serendipitous luck is actually better than skill.

However, in the future, I would suggest that you state that it is your "years of training, combined with exhaustive experience with complex electronic diagnosis and problem resolution that yielded the solution"

Again, good Job!!!

Marty

[billschroeder5842]

Originally Posted by DRM500RUBYZR-1

Oftentimes serendipitous luck is actually better than skill.

Never more true when owning a ZR1

[Curtis]

Originally Posted by DRM500RUBYZR-1

Great catch!!!
Oftentimes serendipitous luck is actually better than skill.

However, in the future, I would suggest that you state that it is your "years of training, combined with exhaustive experience with complex electronic diagnosis and problem resolution that yielded the solution"

Again, good Job!!!

Marty

Yeah wish it was true. 10 years of Aircraft mech, 35 years of hotrodding and fabricating combined with my engineering degree but head doesn’t work correctly anymore due to past events and this ended up being dumb luck.... either way I will bet I’ve not got the only z suffering loose pins in the tps....

I didn’t say but in the last few weeks gave the car a new set of plugs, a new idle motor and bathed the t body in brake parts cleaner..... have a new set of O2 sensors but want to put it on the interstate tomorrow to check mileage then change them to see if I get a change.....

Post up if you check yours and find wires de-pinned or loose

[lfalzarano]

If you can’t be good, be lucky! [emoji16]


Sent from my iPhone using ZR-1 Net Registry

[WARP TEN]

Originally Posted by lfalzarano

If you can’t be good, be lucky! [emoji16]


Sent from my iPhone using ZR-1 Net Registry

A long, long time ago I had a similar problem with my '68 Hemi Roadrunner and similarly got lucky. A stumble and miss at various times that was impossible to track down and everything I could think of had been replaced or properly adjusted. Then one evening when it was a little dark I had the car idling and opened the hood. It was like a fireworks show with all the sparks going from the plug wires to the block and valve covers. The wires had fine cracks and were leaking little lightning bolts. New wires, problem solved. --Bob