Just bought it with 230k.its a 2.5 5 speed.i have replaced the plugs, wires, coil closest to fire wall, upper and lower intake gaskets.when i got it only one code for o2 running to lean.i also checked the timing belt and replaced it but while doing so i lined the crank gear dot to the notch and the 2 diamonds for the oil pump but on the cam i couldnt get the triangles perfect.before i started when in nutrual when i quickly hit the gas it would backfire(puff) from the tb.with the timing as close as i could get it(cam sprocket clockwise about 1mm past the mark it would still backfire out the tb so i changed the cam sprocket counter clock wise 1 tooth and the back fire went away.
I still have power loss every once and a while accelerating.if im in 5th and doing 60 and step on gas it takes for ever just to get to 70.
There are no enging lights on but when i take off and rev it high the engine light will come on till i shift.
Anyone have any ideas?

 

I had the same problem,and I found was fuel related,Replace the fuel filter and performe a fuel presure test(low fuel pressure may cause back fire and power lost)(and engine code for lean condittion)Remember to replace fuel filter fist(check for dirt coming from inlet at the filter if is dirty,i sujest to remove and clean the fuel tank) that how I fix my problem.

 

I replaced the fuel filter.i drained the old filter to see if there were any deposits in it and it was clean

 

check the fuel pressure, the fuel pump could be the problem, any way it is good to know what is the fuel pressure at the system whe you are dealing with missfires, i hope that help..

 

Any one know what the psi is suspose to be.can i use a regular tire gauge on it