I have a 97 Civic EX that had a little bucking to it when I gave it gas and let off and sitting at a light it would feel like someone bumped into the car. I thought it was my tranny and took it to a garage and had them change the fluid and you can't change the filter but i guess you can blow them out. Anyway after that the hard bucking seemed to go away but it still had a hesitation when giving it gas or letting off the gas. A friend that has Honda's said his was doing the same thing once and he cleaned the throttle body really good and it went away. So he came and cleaned mine. It was hard to start like it was flooded and he said that was normal after a deep cleaning like that. After we got it started and running smoothly it seemed ok for about a day then it started to give me a surging idle up and down when in neutral between 1000 and 2000 rpm. When I put it in gear it settles down to about 900 to 1000 rpm and no surging but it throws a p0505 code off and on. I have followed some of the things on this forum on what to try and nothing seems to work. If I pull the tps while running the idle goes to 2500 rpm and runs smooth. If I pull the IACV plug it still surges but the rpm also drops some. If I hold my hand over the throttle body while running it dies. So that tells me I don't have a vacuum leak but at a loss now. We pulled the Throttle body completely off and took it apart as far as you can go and cleaned it really good to make sure dirt didn't get in a passage and causing it. Before I go to the trouble of buying a IACV and throttle position sensor is there anything else I need to check.