Rough idle and acceleration (engine code,51 and 34)

[SolidLifter]

High guys, two days ago I was at a work site and ended up driving my q45a off a cliff. I mean mini cliff, very high curb about 1ft plus. Checked the car out visually and could not find anything broken or bent. The engine was running fine and the transmission was doing what it was supposed to do. drove it back home about 40 miles and it was fine along the way. However I started it up the next day it ran fine for about 15 miles and suddenly it started vibrating and the idle was really rough and the check engine light came on. On acceleration it was rough all through the rev range. It felt like it was not running on all cylinders. Came back home and decided to pull the codes, before I did that, my buddy decided to drive it (engine still warm). He fired it up and it was in the same state it was in when I gave it to him. However, less than half a mile, the check engine light went out and it ran smoothly for about 3 mile. He made a right turn and the the whole thing started again. Pulled the codes on it, and it was 51,34. Injector analysis and knock sensors. Now correct me if I am wrong, but the knock sensor would be going hay wire (i.e. doing its job), if the injectors were not working properly. So I am guessing now I need to check and change bad injectors if any, and probably clean or replace spark plugs. Now I just wanted to know, has anyone else had this problem and is it absolutely necessary to change the gaskets for IAC,TB and EGR when removing plenum. Or can I get away with it, if I am not ham fisted. Any input would be much appreciated because I have to fix this problem ASAP,I got another car I need to resurrect this weekend. Plus for those in the DMV area, A 94 q has been dropped at the junk yard at crazy rays mt airy. Its got less than 150 miles on it and is really clean. There are two in jessup, but they are in pretty bad shape.