New to me truck, not so good when warm
10-12-2014, 08:09 PM
#1
New to me truck, not so good when warm
Hello,
So I've been working on this 1989 F150 5.0 5 speed I picked up. Previous owner put a used mustang short block in it and bolted up all the stock F150 stuff to it, plus a new performance cam, though he didn't know which one exactly...
I've had to change the fuel pressure regulator and the TPS so far.
Now, as it gets warmed up, it starts running poorly while cruising. Accelerating will be smooth, but once you pick a speed and stay there, or lift a little, it feels like it starts misfiring a lot. If you let off to idle, it's smooth again. In neutral and idle, once warm the RPMs get real low. I know that the idle control valve works though.
Could this be signs of a failing fuel pump? Or ECU issue? I pulled codes, and 'engine off' passed, 'engine on' gave me 41, "system indicates lean".
Also, when timing it, I pulled the SPOUT plug and noticed that timing still advances when as RPMs increase- is that normal? I thought it wasn't supposed to advance at all with the SPOUT removed?
Thanks,
Alex
So I've been working on this 1989 F150 5.0 5 speed I picked up. Previous owner put a used mustang short block in it and bolted up all the stock F150 stuff to it, plus a new performance cam, though he didn't know which one exactly...
I've had to change the fuel pressure regulator and the TPS so far.
Now, as it gets warmed up, it starts running poorly while cruising. Accelerating will be smooth, but once you pick a speed and stay there, or lift a little, it feels like it starts misfiring a lot. If you let off to idle, it's smooth again. In neutral and idle, once warm the RPMs get real low. I know that the idle control valve works though.
Could this be signs of a failing fuel pump? Or ECU issue? I pulled codes, and 'engine off' passed, 'engine on' gave me 41, "system indicates lean".
Also, when timing it, I pulled the SPOUT plug and noticed that timing still advances when as RPMs increase- is that normal? I thought it wasn't supposed to advance at all with the SPOUT removed?
Thanks,
Alex
