Ford Repair: 1993 ford escort wagon 1,9 litre sefi, ford escort wagon, ford escort lx

Question
I ran a scanner code check and KOEO read 111,171,172,181,186.KDER read 411,412,536.When this car is driven at highway speeds it suddenly loses power and the accelerator pedal when depressed does'nt respond.Is this something a home mechanic can repair or is it better taken to a professional mechanic for diagnoses and repair? This engine has 143,000 miles on it and is a salvage engine installed by a mechanic 5 yrs ago,it's always had a problem maintaining cruising speed at 65 mph,the mechanic who installed  this engine said he could'nt get it to cruise at highway speed correctly.Code reading's were as follows,171-fuel system at adaptive limits,heated oxygen sensor 1,unable to switch to bank 1,172-lack of heated oxygen sensor switch indicates lean bank 1,181-fuel system at rich adaptive limit throttle.system lean bank 1.186-injector pulse width higher than expected.KDER read 412- cannot control RPM during KOER high RPM check.It's gotten worse lately to where it verily run's due to sudden power loss than it will pick up power again and run correctly for a while than does it again.Thanks for any advice you may have for this problem. Curt    make/model  1993 Ford escort lx 1.9 liter sefi.
.

Answer
first of all sounds like you are perfectly capable of checking basic things yourself-if after doing this you don't find anything then take it to a reputable garage so it can be diagnosed and
you don't throw parts at it.

first be sure and check for vacuum leaks which can give you lean codes and cause injector pulse longer than usual-check all your hoses for cracks especially where the hose bulges when it is plugged into a port-be sure and look or feel underneath intake manifold also.

if you don't see anything write down all your codes and then clear them out either with tool or remove both battery cables and touch them together momentarily-after they are reconnected go drive the car for a while and see which codes come back first then focus on those codes.

be sure plugs, wires, fuel and air filters are all ok. if you get an oxygen sensor code back right away and you haven't found any vacuum leaks i would replace sensor strictly as a maintenance item.

if convertor is original it could be partially clogged best way to test is have a garage do a backpressure test,

don't rule out module or pcm problem although pcm failures on these vehicles are rare-

be sure connections for power and ground at battery are tight and clean
make sure ground connection at engine is good.

good luck and follow up if you need to.