have a 99 Yukon SLT 4x4 with a 5.7. Started having issues a couple weeks ago, particularly with the engine
missing intermittently over bumpy roads. As I'd hit the bumps, my rpms would drop to nothing, gas and oil gauges would move erratically, but no loss or dimming of dash, stereo or headlightsor any other electrical symptoms, and no SES. As the problem worsened, I began being bogged down and almost stalling when accelerating from a dead stop unless I was light on the gas. Within the last two months I've installed direct fit cats, a new fuel pump, tuned up (wires, plugs, rotor, O2 sensors), replaced the crankshaft position sensor. When the problem started, I checked the wiring harnesses and connectors with the truck running and couldn't replicate the symptoms while not under load. Figuring I'd eliminate a few possibilities at once I changed the idle air control valve and ignition coil
, cleaned the MAF and throttle body, and checked the EGR for build up (it was reletively clean, no blockages). After I finished and took her out on the road for a test run, I got a block from home and stalled. Truck started fine, idled fine, but once I put it in drive and hit the gas, it died. Tried starting and driving several times with no success, but put it in reverse and she ran like a champ all the way home. This is where I am now. Truck starts, idles fine, but when I put it in drive and hit the gas it dies. Reverse works perfectly and seems unaffected and still no codes or SES.