Ok guys...I have a 1995 5.0 that is now driving me crazy. It runs pretty good except at cruising speeds.(other than a slight hiccup at idle every now and then) When I lightly accelerate, it wants to ping and buck.
I just bought this truck last year but here is what I replaced trying to eliminate this problem
Plugs/Wires, Cap/Rotor, TPS, ICM, Injectors

One thing I noticed is that with the SPOUT in, the timing light isn't steady like when it's out....

I'm not getting an CEL or codes at all

I drove it with the SPOUT removed and it idles perfectly, doesn't buck under light acceleration, but you can still hear a slight pinging.

Timing is set at 10 BTDC

EGR system is working fine too

Any thoughts?

 

I borrowed a new EEC from a friend who runs a parts store...no change.

I ran KOEO, KOER, WIGGLE and STATE tests...everything checked out fine

So I ran a cylinder balance test 3 times... 2 times it said #6 was weak and once it said #5 was weak.

It seems like I've eliminated everything except the distributor or the harness. I double-checked the plug wire routing just to rule out crossfire, everything seems okay.

An ideas?

 

There is a sensor... i can't actually recall the name, i want to say PIP (then again, i might be thinking about *****), i think it's inside the distributor and has something to do with the spark.

 

Pick-up assembly. Be sure that the balancer hasn't slipped.

 

It was the PIP....changed the distributor today and so far, so good!

 

Bullseye! i love when i do that, glad you reported back, it's good finding out the cause and it will help others with the same issue.