TBI is surging with steady part throttle in open loop when cold. Especially when it's been driven - shut down for an hour - and restarted. The surge is like a whup-whup-whup-whup until I add throttle and rev it out. It goes away after I drive it for a minute or it warms up to closed loop. It does this with both old and new TPS but with the new TPS the acceleration stumble remains. All other sensors are new. Any ideas? The open loop/ closed loop is throwing me.