I just bought a used engine for my 1988 lincoln and its reading history codes of 91, 41, and 34. What are these codes

well first go to GM and ask for RPO look up from VIN
learn the engines (day1new) RPO code!
first.
the dealer can use the engine serial number too.
the service manual shows how to find, all VINs
engine and tranny seriels. in chapter 1.
Gm makes this all so easy so do it. ask them,.

I couldn't find engine code for 420 but may be body code take to AutoZone for free test and code meaning

E52=memory (history) has been lost.try ERASE all your codes and see if any come back.1.turn Ignition ON, Engine OFF.2. Push and hold the OFF and WARMER buttons until all the segments on the display illuminate and as soon as the codes start to appear, Push the OFF and HI buttons and release them until you see .7.0.
3. Turn ignition OFF.

it is near the thermostat housing

Is the check engine light on? If it is get the codes read. It also could be a bad vacume line off the fuel injector.

you may need a better scan tool because the manufactor has codes that the cheap scanners can not read

There are a couple of parts you can try and if they have not coded on the cars computer, a dealer may be able to look at service bulletins. There is a differential speed sensor and an antilock brake sensor. You can have locking clutch paks and may require a special additive. An old fashion U-joint can vibrate under load.

The good news is with a Vin# the dealer can pull up the entire service history if the car was serviced under warranty or in a Ford dealer anywhere. They just do not want you to know the past owner.

that weight oil will be sufficient but use high mileage like castrol high mileage of same weight for more protection

did you replace the egr valve

1986-89 Lincoln Mark VII Stereo Wiring Constant 12V+ Green/Yellow Switched 12V+ Yellow/Black Ground Red Illumination Blue/Red Dimmer n/a Antenna Trigger Orange/Blue Antenna Right Rear Front Speakers 6 1/2" Doors Left Front (+) Orange/Green Left Front (-) Black/White Right Front (+) Pink/Blue Right Front (-) Black/White Rear Speakers 6" x 9" Rear Deck Left Rear (+) Pink/Green Left Rear (-) Blue/Orange Right Rear (+) Pink/Blue Right Rear (-) Green/Orange