My 2003 nissan altima 2.5s reached a high mileage point 91,

My 2003 nissan altima 2.5s reached a high mileage point 91,000 miles.?
The engine light is on and my oil hasn't been changed for 5,000 miles now, because of my friend, I was out of town for two months and comeback and the engine light is on, also when im in park and change into gears the from P to D or R, the car tends to jump when switching gears, now I checked to see if im loosing any performance by dynoing it and it read 164 HP, what major maintenance work should I do to ensure that the car will last for another 100,000 miles more, so far I have only had oil change done to the car, im thinking now it needs a new belt if there's a crack in it and also radiator and transmission flush, the last oil I used was Castrol GTX High Mileage

You have lots of miles on this car. you must ask yourself what am I going to do? Am I going to keep or replace the car. The engine light on means its time for a big service. you may want to changed the oil and filter every 3500 miles. Things you have to think about like, engine timing belt and its condition, head gasket and is it leaking, manifold bolts and studs, are any broken and or need replacing. You seem to use up money on performance testing but you did not say what you have spent on service. As far as jumping, there are many things this may be. My advice, have a good Nissan mechanic use up some time going over the car. It may cost you a two hour time charge. If they do it right and go over the complete car, you will at least know where you stand or do what lots of people do, drive it till it stops, then worry.

I am your source as I was a Nissan Datsun mechanic for many years. I can not give you a better answer than what I just have said. I wish you good luck with your car. Mark

sounds like possible motor mounts torn,any cracking in timing belt should be replaced at 80,000 miles,engine or oil light?
engine light means problem with engine monitering systems possible 02 sensors,check your holders manual for service schedule,and maintence service light reset procedure.sounds like your freind beat the shi_out of your car.

maybe the fuel injectors are cloged.. attempt using one of those fuel injector cleaners use STP I think its called that

The 5,000 miles is no big deal. Nissan recommends 7,500 and buyer Reports has proven 3,000 miles is overkill. 91,000 miles on an Altima is no big deal. you have got at least another 100K in it.

Test your antifreeze with a floating ball tester. If it is still bright green and good to zero I'd leave it alone. New belts may be a smart idea. The car has a timing chain so no timing belt substitute is required ever.

Get the auto trans liquid and filter changed, but go to somebody you trust. I have had guys attempt to show me metal shavings hoping i'd believe I needed a transmission rebuild.

Altima's a good car.

Change the oil

here's what you really have to do:
1. Change the oil and add a can of MOA by BG merchandise, this will
breakup any oil increase caused by lack of oil changing.
2. Change the air filter, also keep in mind the fuel filter is inside the
tank, so you don't have to change it out.
3. Do a coolant and trans flush.
4. Do an injector flush and add a 44K fuel additive by BG
merchandise and a throttle clean.
5. Have a certified Nissan tech or a certified ASE tech diagnos
your "check engine" light
6. While their there, have them examine your timing chain, if it rattles or ticks bad and aided with your lack of oil changing don't
be surpised you may have to do a timing job or at worse, replace the engine.
7. as well, change the sparks plugs with NGK plugs only.