My daughter's 91 5.0, 700rv Z28 dies after it's warmed up upon deceleration. As long as it's cool it runs just fine. The speedo doesn't work right now and it's throwing code 24 so I know I need the replace the VSS, but would this cause the dying? Does that speed sensor effect the timing in any way? If not, should I replace the ignition module? Is that my best next step?

Also, I realize this post looks like it may belong in the Transmission Forum but the dying is my main concern so I thought I'd get good input in either place.

Thanks in advance for your help.

 

Short answer - replace the VSS and it'll most likely fix your stalling problem.


Long answer - The computer in your car has a table called "throttle follower" which raises the engine RPM for a specified length of time when you let off the throttle over a certain mph (12mph? I forget exactly.) to prevent the engine from stalling. If the computer doesn't get any MPH reading, it doesn't know to add engine RPM when you take your foot out of the throttle, and that makes your car stall.

 

That's a great answer. Thanks.

 

The VSS did solve this problem. Thanks to all for the help.

 

G-reg, A big THANK YOU for that info. I've been having IAC & VSS problems. Noticed the idle would stay at higher RPMs when I released the throttle. Thought it might be a problem. So nice to know it is normal and the reason why. One less thing to to worry about.

 

Well documented on here
https://www.thirdgen.org/forums/post...740-post4.html

No VSS signal also locks the ECM in block 4
https://www.thirdgen.org/forums/post...475-post6.html