Hello folks, I have been read a couple hundred threads and responses on this site since I found it all in hopes to find some cures for my stumbling, surging, pinging, F150. I took the information I found and proceeded to clean the EGR, and IAC valves as well as the entire throttle body and set the timing by the directions listed here. I have to say the truck now runs perfect and has much more power. I thank you all and God bless you.

 

that was a very nice post.

tell us more about your truck and welcome to fte.

 

I bought a 90 F150 with a 5.0 and automatic. I sold a lot my 02 Ranger edge and they paid it off and gave my the 90. I couldn't justify paying 300 a month for something I drove 6 miles a day. The 90 was running very rough at idle mostly with a surge and very low idle that would drop low enough ti kill the motor. It would also ping like crazy after it hit third gear.

I took the EGR valve off and cleaned all the carbon out. I took the IAC off the side of the throttle body and cleaned it out as well. I used plenty of throttle body cleaner, some bluck prep brushes, and compressed air. I alto too a fine wire cup brush on a drill and cleaned the throttel body tubes and the intake as far in as I could go. Then I used a shop vac to suck out all the nasty stuff.
The throttel body was shiny and clean so I buttoned it all back together and then set the timing by first disconecting the spout plug, which I never would have known to do, and founf the timing to be around 20 deg. so I set it back down to 11. cleaned out the air box and tubes, cranked it up and sat back and listened to perfection. she runs great now with a great power band at all speeds and no more surging and dying.

I was looking for some sort of MAS or MAF to clean but couldn't find anything like that. If you know where or if there is one on a 90 302 motoer I would sure like to know about it.

 

Your 1990 motor is speed density. No mass air sensor to worry about. There's nothing like the feeling of fixing your own truck yourself. It satisfies me every time I do it.

 

What's this about setting the timing? I thought these things were computer controlled.

 

The timing advance is computer controlled, but the base timing is set by rotating the distributor.