4.3 Stumbling at mid to hi rev
Got a 91 S10 4x4 4.3liter auto that stumbles at mid to high revs. With a timming light the timing can be seen retarding 10-15 deg when the problem kicks up. Taking it down the road is just about inposssible, it starts to booge down with no power. Fuel filter was changed, has a new dist cap/rotor, tried new spark contol module, new knock sensor, looks like fuels pouring good during the act, timing is stable at idle. Could the timing chain be the culprit?
Second engine with 100k on it, 3rd tranny, rebuilt transfercase.