1988 f350 460 efi. A lot of new parts started trying to stall or die easy and runs a bit richer but that seemed to have been a consiquence of what evers not working. It hasent actually died just does for a second then runs fine. On the high way theres no problems unless its stop and go. And check engine light is off on high way. Self test codes 22 33 96 98. Map has pressure contion rest eec reset no change. Im concerned about 96 if anyone has insite its much appreciated.

 

Second selft gave gave same godes third gave 77? And 21

 

You need the info out of a 1988 PCED so you can chase down the codes using the directed pinpoint tests
I have a 1989, it will be real close if not the same
What trans do you have? E4OD or not makes a difference

 

How are you getting your codes?
There is no 98 code for yours
This should get you started

 

 

 

As you can see from that J94 test, you need the proper 88 schematic to see if yours has the splice to the FPM
You are looking to do some wiggle testing
Good luck
007

 

Zf5 trans. It repeatedly puts out 98 its in there somehow. And 21 comes out. Also what could cause the 22 codes thats consistant?

 

You will have a hard time with DF 90 to DF 93
Getting a vacuum pump (on the MAP) to 25 inches is difficult / impossible
Substitute a known good map sensor is the test
Plug in a new MAP and watch the 22 go away

 

 

 

If you do not have a problem before performing DF91, you will after on an old truck
You hope the new map fixes it

 

21 is the same as 98
No such code
You reading a flashout code from the light or what?
How are you obtaining codes?
You can sure chase your tail if you are barking up the wrong tree

 

Self test. Reading flashes yes.the map is new but cheap ill replace it. I only got 21 once so idk but i get 98 every time i run it.it stumbled on the highway this morning. Kinda getting worse but i ts running rich from the map response. And i ran that tank out of gas so maybe that was part of the problem? No issues on this tank so far.

 

find a scanner that will hook up to scanner port and check for data from your front O2 sensor .unplug and clean out all the wire connections you can reach .