Trooper firing on only 3 cylinders. Need suggestions on what is wrong. on 1998 Isuzu Trooper

My trooper is firing on only 3 cylinders. 1,3,5 will fire fine but 2,4,6 are not getting any power. Have taken the good coil packs off and put on the side that is bad and the good ones then don't work. Timing belt was replaced and has been checked twice to make sure it was set right. My mechanic has taken it to his electrician and they have determined it is electrical but computer does not show a problem. Love this vehicle and would prefer to get the problem fixed then just giving it up. Trooper has 159,00 miles on it. Any suggestions on how to fix this?

by in Petersburg, VA on November 03, 2013
4 answers
ANSWER by on November 04, 2013
Check the following; sparking plug leads are correct sparking plugs are all working, if it is efi the injector are getting power, check firing order.is there a backfire? Check and clean all earth contacts.
ANSWER by on November 04, 2013
Compression readings for ALL cylinders would be handy to start with! Is the computer seeing the misfires (light on)? Is it 'obviously' misfiring (running rough)?
ANSWER by on November 04, 2013
agree with 1 AND 3
ANSWER by on November 05, 2013
Same belt as on the Honda Passport--Maybe same insane procedure for cam positioning too? All I know is there were several different positions for the cams to go , and still line up with the marks , but only one position works.Single pulley on outside , but twin cam ,gear driven inside. Have crank OFF top dead center to set cams Turn pass side cam and let it 'jump' to its' own stop (maybe 3-4 times) until the mark lines up. Same routine on drivers side except I think the mark stops just a little before the spot on the backing plate. ............Factory service manual would REALLY be good , cause I could be wrong!!!!!!!....Good luck.