last week i was about to do a compression test to my 99 gs. in the process of trying to remove my spark plug from first cyclinder hole i had to put it back and save the comp test for another day. well about two days later my SES light came on. today i took it to advance auto parts to get it checked out. computer read PO301. rep at auto parts said i have a misfire in #1 cyclinder hole, and that it could be fuel injected related or spark related. i went home to make sure i had tighted it. spark plug seems to be in fine. could i have damage something internally in #1 hole? what can i do to get rid of that SES light? i want to try to fix it before i have to take it to a mechanic.

Is the car running poorly too or do you just have a CEL? If you really had a misfire you would know about it. Take the plug out and inspect it for damage if it's bad then replace them. It could also be a plug wire so check those too. Spark plugs are cheap, so if it was me I would just get new ones do the comp check and replace all the plugs with new ones.

I edited to the wiki!

i change my spark plugs like 3 weeks ago when i got my UDP put on so i don't think anythings wrong with'em, unless i damaged the first one. as far as noticing any changes, only that my car seems to bog down when i start off in 1st gear. but i been having that problem before the SES light came on.

i did a compression test today and got in cyclinder #1-90,#2-215,
#3-200,#4-220. could this be why my SES light came on? what does this mean for Cylinder #1 being so low? what should i do?

please, does anyone have any suggestions as to what should be my next step after getting those reading from the compression test. what could be the problem in my #1 cyclinder hole since it's reading at 90.

I don't know if it make sense but maybe your #1 spark plug is loose.
If it's loose then it may not be grounded properly (reason for misfire).
Maybe you lose some pressure around the # 1 plug and because if that you have a lower compression in that cylender.

I'm not a mecanic so, if it don't make sense ,forget about it.

95 Talon ESI
Mod: Custom Turbo
Modified T3 turbo on custom manifold
4 extras injectors
SDS auxiliary injectors controller
Modified 1G side mount Intercooler
Custom stainles Steel IC pip