newbie with questions engine studder

[orange342]

hey guys i have a new to me 86 mj mostly stock that i can tell 180,000 mile 2.5   my problem  is when starting the engine it cranks over fires off and has a stumble like its running on 2-3 cylinders this happens for 3-5 seconds clears up and runs like a champ, it runs fine down the road and has good power with no skip   my issue is only on start up it has new plugs and wires i also pulled intake cap off and watched the injector it does not produce much spray for start up  but does have a nice uniform spray once running  any help would be appriciated thanks  

[cruiser54]

Begin by cleaning the ground strap connection at the firewall. Remove the bolt, scrape the firewall to bare metal, polish up the terminal, and reattach.