when it rains, it pours... 700R4 is failing, and just as I track down a used one, engine starts running poorly... The thing had a minor glitch for a year or two, where at 4 or 6 mph, light throttle, going up an incline, the rpm's would jump up and down at 2 or 3 second intervals. Now this new problem seems to be similar but 100 times worse... at low rpm's , the thing barely runs, and backfires through TBI sometimes. Once it hits 25-30 it smooths out, and by 35, it picks up power again. Trans is shot, but I think this engine problem is unrelated. It's in an 89 Suburban. I had broken a wire loom for the plug wires when I put a new set on, and I saw a wire that touched the exhaust manifold and burnt the insulation a little, but I put an old one back on and still same problem. Any clues where to start looking? I lost my Haynes manual or else I would have started troubleshooting it already. It is really hard to take off from a stop until I get it up to speed. New fuel filter a month ago improved performance a ton. I am wondering if it is in the fuel pump, sensor/computer or timing related issue, or what? I am no ace mechanic, but once I get on the right track I can figure things out. Thanks!