Old school proplem solver

Ok this can be applied to just about any vehical ever made ...but my experience is with ( for this case) my 1991 jeep cherokee..i had all kinds of proplems and codes...they consisted of hard starting, reving up and down, cutting out,(engine dying), worse and worse gas milage..stumbling..o2 sensor codes( fault o2 sensor)..bad isc motor..bad map sensor...bad temp/thermostat and my brakes kept getting worse..(softer and softer...so i started posting my proplem all over the net and even broke down and took it to a jeep service center...i spent well over seven hundred dollars and still most all of the proplems remained...so i referd back to an old and very simple way to search for proplems with any motor...(cheapest way first)...lol well i guess not first..at least not for me haha..i started unpluging the different sensors while the engine was running to see if there was any change and every one seemed to change things a little ...so i then took a can of carb cleaner and started spraying ever gasget surface and vacume hose...!!!!..i found that the engine changed pitch every time i sprayed the intake gasget...!!!..so i bought a new one for ten dollars ...spent 4 hours to replace it .. and it fixed every one of the proplems i had...it sounds crazy but if you put a little thought behind it ..it makes perfect sense...o2 was reading faulty and lean(more oxygendue to leak)..brakes were getting softer(due to drop in manifold vacume) map sensor was reading faulty and causeing stumble and cut out (also due to drop in manifold pressure) temp/thermosate reading due to idle air temp (which needs to coencide with temp sensor) not recieving proper air flow reading also due to leak...well as much as i can go on about this i am just posting this where i can i hopes that my adventure saves someone a little money....remember i spent over 7 hundred before figuring out this simple ten dollar fix!!!! and since the intake and exhust share a common gasget it is pron to leaks....good luck and i hope this helps