Praying that someone can help me diagnose this issue I'm having. At slow speeds and under load the oil pressure drops to 5ish and stalls out. Also while driving down the road it'll cut in and out for a few seconds. The motor seems very weak to me vs what it should be. It's a 89 k1500 5.7L TBI Here's a list of what I've done so far. - Replaced the TBI base gasket. - New fuel pump and fuel filter. - All rubber fuel lines. I did have to patch the old lines into the new lines at the pump. - Oil and filter 10W30 - 2 1/2 X 10 air filter - New MAP sensor and IAC sensor - 2 new vacuum lines - Changed the timing from 14 to 8 ( which helped the throttle response before the truck got to fill temp. Them the "hiccupping" got worse) - visually checked the injectors. Loaded it in the driveway and had it checked by a friend. - New plugs and wires. Checked the firing order also From the discussion I had with someone he's mentioned the EGR being clogged and to delete that, torque converter, distributor. The butterflies on the throttle body are a little pitted up but I don't think it would cause that big of an issue. It's got the stock exhaust manifold and cat but it fell off after that so there's no muffler for back pressure. Which im in the process of custom designing a system for it. Just trying to get the truck to run a little more stable. Any suggestions or places to start to figure out this issue? I'm tired of just throwing parts at it and wasting money at this point.