Loss of power, wont go over 40 mph, and takes a while getting there...

a 35year old car. never seen one me with less than 10 problems.
100% expected. USA car in OK state clearly told and nice!
NO ENGINE TOLD (size) car is called N13 you generation car.
auto tranny and with 4wd?
USA PULSAR NX, IS 1.6L DOHC OR SOHC ENGINE.
ALL ARE INTERFERENCE ENGINES,
NEVER IGNORE THE TIMING BELT . REPLACE IT FIRST.
so is and engine problem, not transmission failure to up shift, correct>? this fact must be learned first. or off base tests go.
engine Power loss has 50 causes. (electric or pure mechanical)
but in basic engine theory (ASE) and gas engines, and otto cycle engines,
the ordered list is.
1: good engine. . EGR not stuck open. CAM BENT NOT BAD OR WORSE SLIPPING. << FAST DRIVING THIS WILL Bring destruction.
2: good spark ,cap, rotor , HV spark wire set and plugs.
when 40mph cliff of failure hits, is engine misfiring? violently?
or is power loss smooth loss of power, RPM fails to rise more. but falls.
the former is spark bad. (ckp ,cmp or caused by cam belt slip)
#3 fueL
if slow smooth power loss,fuel pressure may be low.
if slow gee? the belt on the cam slips. never drive like that.
day one traded to this car, the belt is first ( I just hate bent valves)

possible bad fuel cap vent?

If the engine has a miss or power loss, the check engine light should be on.
Is it ?

I have a 1993 Taurus GL V6 3.0L..I"am experiencing a loss of power. Hesitates on acceleration Only when It's cold.When is get hot it runs very good. I have Replace Spark Plugs Cap & rotor were change air filter & fuel filter & TPS/EGR..... & it has a rebuilt ENG in it...this could be a sensor. But which one could it Be?

What Can This Be?

This engine is fully electronically controlled, so you need the dealer to do a full diagnostic of the engine control system, it is the only way to get to the bottom of this. Make sure you can show the dealer exactly what is going on otherwise if they can't duplicate the concern and no fault codes are present they can't fix it.

I had a similiar problem on my 1999 Dodge Ram 1500 Conversion Van. It ended up being a partial collapse of the catalytic converter which didn't allow adequate exhaust. The problem only showed itself because I could not get over 55 mph going up a small hill.

Most likely the orifice tube/expansion valve needs to be replaced. Depending on the type of system, you will have one or the other but they both perform the same function. The expansion valve is typically located at the evaporator inlet. Orifice tubes can be located at the evaporator inlet, in-line between the condenser and the evaporator, or in the condenser outlet. You will have to discharge the system in order to replace. Not very hard to do.

The rod knocking is caused by loss of oil pressure. Did the oil light not come on? That light is red, red means stop. Do not start this engine again until the problem is corrected.

Have you checked the oil level?

MAF bad

check spark plugs. and igntion coil.