Intense Shaking in idle/ flashing engine light

[ColorofKris]

2003 Discovery Series II 97k

Got into my truck this morning to go to work and when I turned it on it started shaking intensely and the engine light started flashing.(have not checked any codes or anything, havent been home) Yesterday had put cross member spacers on (Recently replaced front drive shaft), and as well the factory exhaust (a friend of mine helped me rig up a cherry bomb on it, wouldn't line up right so I put the factory back on.) Ran fine all day after that, until this morning.

After reading up I'm guessing it has to do with 02 sensors which should be changed every 60k they say, would fiddling with the stock exhaust cause that to occur? I also am planning on replacing valve cover gaskets because those are leaking, I haven't seen any relation between the shaking and the valve gaskets in any write ups of the matter.

My next guess is spark plugs. They look to be recently replaced (only had it for a month or so now) they are 8mm blue magnecor by the looks of it and Bosch platinum spark plugs.

Where should I start? are there any other ares of concern I should check or get checked? (im not super mechanical but Im learning, so if its super technical i may need some explanation please and thank you!)

 

[Disco Mike]

If you want some help, first get the fault code numbers then send me your number and I'll call you today.
In the mean time, leave the 02 sensors alone cause they are not causing this problem.

 

[ColorofKris]

If you want some help, first get the fault code numbers then send me your number and I'll call you today.
In the mean time, leave the 02 sensors alone cause they are not causing this problem.

After reading into it more and such I agree its not o2 sensors, im working and moving today and the remainder of the week so dont have much time to work on it . Was debating on taking it to a professional to have it checked.