m isses alittle when idling misses under load but can`t hardly feel it at high way speed also trans shifts hard from 1st to 2nd but shifts fine after that supposed to be new trans this is my first post any help would be appicated

 

To help us help you, post the size of engine you have.

 

i`m sorry it is a5.0

 

Go to Ford Fuel Injection How To Run a Self-Test to learn how to pull codes w/out a code reader. This will help in the diagnostics.

I had a problem on my 91 some time ago that was similar to yours and it turned out to a bad MAP sensor. You might try unhooking the MAP vacuum line and plugging off the manifold and sensor to see if that makes any difference.

Otherwise use the above website to pull codes. If you have trouble counting the CEL blinks, this code reader Equus 3145 - Digital Code Reader | O'Reilly Auto Parts is cheap and easy to use. I picked mine up in store at O'Reilly for $30.

Let us know what you find out.

 

Have you changed the plugs, wires, cap and rotor?

 

wher is the map sensor located

 

Ford Fuel Injection Manifold Absolute Pressure Sensor (MAP) Looks like this and should be on the firewall I would think.

 

thanks i will try that

 

Hey, my 92 is doing the exact same thing. 5.8 litre, 2 wheel drive, E40D transmission. I have tried new plugs, wire and cap. My EGR was weak and that helped a lot but it still misses exactly as yours particularly under load (3000 pound trailer) and after about a half hour of driving it becomes very weak and with a strong fuel/exhaust smell. I rebuilt the engine 15 months ago and this is the only problem which is a recent. I am going to test the MAP and see what results I get. I will let you know. Let me know if you discover anything.

Good luck.

 

thank you i will let you know if i find out anything

 

Okay, as I said before my truck was doing everything that you described. It was also running hotter then usual. So, I started testing the MAP but then decided to just buy one since this one was at least 15 years old. The idle immediately smoothed out and I have driven it for about 30KM with my trailer (3000 lbs) and no issues. The shifting from 1st to 2nd also seems smoother. I did also change the PVC at this time. I have since driven it about 50KM without the trailer and it is running great. The low idle is now steady and smooth and no sense of it missing when idling or on the highway. So the MAP seems to have solved the problem but I will know better after a week of driving or so just to be sure.

 

thank you i will try that ansee if it helps mine thank you

 

An up-date. Ended up taking an unexpected trip (over 200KM), a lot of highway and some city. What a treat, it is running so smoothly and now it has lots of power. The engine stays nice and cool like it used to. It is also starting very easy now. Before starting the engine when it was hot, within 5 - 10 minutes after shutting it off , it was very hard to start. Not a problem now.

If you have already changed your wires, plugs, rotor and cap, and have checked for vaccum leaks then I would start considering the MAP.

 

thank you iwill try that today does your trans shift better from 1st to 2nd

 

The transmission shift is now so smooth you need to pay attention or you will miss it. The MAP sensor has made an incredible change on the vehicle.