Jeep Wrangler problems

Hi All, is there a workshop preferably in Pattaya, but can travel to Chonburi or Bangkok, who can hook up the engine to a diagnostic machine, the problem being when I drive over rough ground, the engine cuts out or will not rev, having to drive with one foot on the brake the other on the accelerator when driving down hill. Since arriving back in Pattaya have tried to create the same problem, but with no avail, this is the second time this has happened, the check engine light also comes on. The Jeep is able to run on petrol or LPG, the same problems with either fuel, the problem will sometimes rectify itself, then re appear.

Thank you in anticipation,

Tom