Hammack1975
Newbie
hi guys. I have a 1991 K1500 that was my first pickup that I have been restoring. Half way thru the project it got put off for several years because of a change of employment. I've now started the project again, and run into an issue with my engine. It's a 350 that I built. It is mainly all stock except bore .030 over on the pistons. It has about 10,000 miles on it, and ran fine after the build. I haven't driven it much at all over he past couple years except to crank it and let it idle to keep it running. Now it has a stumble during acceleration. It cranks perfectly and idles fine. If you mash it to the floor it takes off and pulls strong with a slight stumble at around 2500 rpm I'm thinking as I have no tach but it's barely noticeable. Now if you ease off like normal everyday driving it stumbles as if it's running lean when accelerating slowly thru the gears stumbling hard in second and third gears. It will idle all day with no issues. I have replaced entire ignition, plugs, wires, cap and rotor. Checked timing, And fuel is clean and new. I did notice yesterday it threw the service engine light on but it doesn't stay on after switching the truck off. One friend of mine leaned towards possible injector issue, and another said EGR could be culprit. I'm relatively new to working on these TBI units. Just never had much wrong with them so any info or directions to look will be greatly appreciated. Considered purchasing a scanner to see if any codes were thrown but not sure exactly what unit I need to do that yet. Thanks in advance.