Different year but had a suburban a 93 that was acting similar. Thought it was the tranny. Normal driving was fine but when getting on the freeway or anytime I really had to put my foot in it all show no go. Thought for sure the tranny was slipping. Would drop a a gear and things would be fine or it would eventually slip into the next gear and all was fine. Ended up being the speed sensor for the tranny. Tranny was not shifting correctly.
