TBI troubles- "sticky" throttle

[Flmarine71]

Hi guys- just picked up a 88 silverado 1500 with manual transmission. Not used to TBI. The throttle/pedal has resistance when you first get into it and then lurches free. Happens when the truck is running and shifting gears (most noticeable in 1st and 2nd) after throttle goes back to full close. I've researched here and it seems the likely issues are:
1. Throttle cable catching- I replaced with new cable but same issue. When truck is not running, there is no initial resistance in pedal.
2. Dirty TBI- inside doesn't appear dirty at all but I went ahead and sprayed throttle body cleaner in and let sit with no real difference.

There is a 3-4 second delay when blipping the throttle by hand (cable disconnected) before idle goes back down. I am assuming this is what's causing the "lurching" once the resistance goes away.

Could a bad TPS sensor cause these symptoms? I need to get some probes for my multimeter and planned on checking per service manual. Any other items you recommend checking? Thanks.