Is there a relay to provent maximum acceleration the engine?
Yes. It has limp mode and a Governor both. One to prevent over- speed and the limp mode to prevent further damage to your engine in the event of a transmission problem - http://www.jeepsunlimited.com/forums/showthread.php?502505-Limp-mode - http://www.jeepsunlimited.com/forums/showthread.php?442673-42RE-Governor-Pressure-Solenoid-and-Sensor-fix
But re-reading your question Soulmanblue, if you are asking if it has some sort of device to keep it under- powered.. well, no
Looking for a Used Grand Cherokee in your area?
CarGurus has 72,252 nationwide Grand Cherokee listings starting at $700.
Search Jeep Grand Cherokee Questions
Jeep Grand Cherokee Experts
Related Models For Sale
Used Cars For Sale