My 1999 GMC jimmy with the 4.3L was running great untill today. This morning I got in my jimmy headed down the road and the engine just started surging and sputtering.

It starts on one crank everytime
It idles perfectly
As soon as the truck gets to operating temp the engine runs perfect.
Theres no codes

About six months ago I fixed my leaking lower intake manifolds, I replaced the distributor cap and rotor, the spark plugs, cleaned the throttle body
checked out the spider injecter system. I just cleaned the contacts in the MAF sensor and still no change.

This has me stumped any help would be awesome.

 

Any change in fuel?

 

no i've been going to the same mobile gas station that i always do, the fuel pump and filter are less that a year old and i can hear the pump working perfectly when i turn the key on.

 

I'm thinking Fuel as well.
Any chance you could do a pressure test while driving, that'd be best done from "after" the Fuel Filter.

 

well it looks like its fixed. Ever since I cleaned all the gunk off of the MAF sensor its runs perfect. It must have taken the pcm a little bit of time to see the change. I also finally threw my K&N filter in the trash and went back to the paper filters, I shouldn't have to clean that oil and dirt off of my MAF and no I never over oiled the filter.