Rough Start and back firing

[TexasMalexus]

Ok I have a 91 XLT and when I start it up the engine shakes pretty badly and it hesitates to start up and sometimes back fires. Then once it finally starts runs smooth as glass. I've got new plugs, wires, coil, fuel filter and regulator, and the fuel pump is fine. I did notice a little while back that 2 of the spark plugs were coming out with oil on them a few weeks after changing them. I was wondering if this could be an issue with the valves maybe?? Any help would be appreciated I am new here.

 

[bloxxbmw]

This is a good question... I have a very similar issue reciently. When I first start up is shakes violently... but after I start accelerating, it goes away. Anyone have any ideas? It all started after I added a fuel injection cleaner to my tank.... could there be any correlation?

 

[colecifer]

I also am experiencing something similar after adding fuel injector cleaner. Not every time but some of the time on start up the engine will idle pretty rough until i start giving it some gas to drive and after i get moving for a little while. Its not something I'm worried about yet but it is kind of annoying.

 

[wired_af]

Mines been doin the same recently, start it up and it idles rough then goes away about 5 seconds later...

 

[Tbars4]

i hate to say it but mine just started that this week...only on first start of the day for about 5 seconds...it must be a opec conspiracy, lmao....

 

[Mud Bug 94]

i could be a valve problem... it will go away after its warmed up because the valves get hot and seat right in the head..any one following me here? my suggestion would be to do a compression test on the cylinders that show oil residue on the plugs aswell as a good one for a control in this experiment.....its gunna be tough because you have to do it with the engine cold...

 

[clvineyard]

yeah i had a very similar problem with my 93 but it would only spit and sputter for 10 secs or if i full throttle it. it did that for a year i just learned to live with it. then it started pouring coolant out of the lower intake gasket. Replaced the upper and lower gaskets has NEVER came back and runs awesome. i got 215000 miles on this truck too and it went out around 189000 what milage you got on yours? my problem was a crack in the lower intake gasket and it was sucking in air which was making it sputter. but it would only happen when it was hot. hope this helps

 

[wired_af]

Just checking back, mine just started running like crap full time. Found a spark plug wire to be corroded where it plugs into the coil.