I am experiencing hard starts and stuttering/stalling during acceleration. Actually idles well when started. TFI replaced last month. Got a Code 53, so I replaced the TPS today, same hard start and stuttering. Can the transmission modulator cause this? I have used FI cleaner, and the fuel pump and filter are new within 4 months. When I am cruising, it can drive all day...any ideas? Thanks!

88 Bronco, 4.9L C6

 

Replacing a part rarely fixes a code - the code doesn't mean that any part is bad. It means you should diagnose that system/circuit to find out why the computer is getting unexpected signals from it. You could still have a problem with the TPS - but you're gonna have to diagnose it to find out. The Haynes manual shows how.

 

Can a bad TPS, or system cause hard starting? thanks, and your point is well taken

 

Since the TPS tells the EEC where the throttle is, it can definitely affect starting. In fact, if the EEC sees it as WOT, it will shut down the injectors because that's how you clear a flood condition (just like with a carb).