IsaakMooar
Newbie
I’ve got a weird one.
I recently bought my 1994 k1500 with the 350 from a guy in my area. He had owned it for a short time and the owner before him put an aftermarket tbi setup with a spacer and different ram style intake in it. To my knowledge that is the extent of the aftermarket parts atleast on the engine side of things.
It ran fine but had a dtc light so I checked it and it read code 42 and that was the only one. After going through the diagnostic trouble tree I found that the connector used to make an open on wire 424 (ic bypass) to set base timing was unplugged. So I plugged it back in and started it and the light went away. I then soon realized it had developed a misfire at idle. The idle seems to be at the same rpm although maybe slightly lower around 700 or so (I have a cheapo tac from autozone so who really knows) and the misfire is pretty steady but the idle doesn’t seem rough other than the one misfire that happens every 1-3 seconds. If i wack the throttle it doesn’t miss or hesitate. And while accelerating or cruising it doesn’t seem to miss at all. Only when on idle. Could it be a bad pcm or icm. It ran fine on base timing. It was slow but I figured it’s a tired ol 350. It also isn’t throwing any other codes. I’ve also only driven it about 5 miles since fixing the original code so it may throw one later on. Please help I’m very confused.
I recently bought my 1994 k1500 with the 350 from a guy in my area. He had owned it for a short time and the owner before him put an aftermarket tbi setup with a spacer and different ram style intake in it. To my knowledge that is the extent of the aftermarket parts atleast on the engine side of things.
It ran fine but had a dtc light so I checked it and it read code 42 and that was the only one. After going through the diagnostic trouble tree I found that the connector used to make an open on wire 424 (ic bypass) to set base timing was unplugged. So I plugged it back in and started it and the light went away. I then soon realized it had developed a misfire at idle. The idle seems to be at the same rpm although maybe slightly lower around 700 or so (I have a cheapo tac from autozone so who really knows) and the misfire is pretty steady but the idle doesn’t seem rough other than the one misfire that happens every 1-3 seconds. If i wack the throttle it doesn’t miss or hesitate. And while accelerating or cruising it doesn’t seem to miss at all. Only when on idle. Could it be a bad pcm or icm. It ran fine on base timing. It was slow but I figured it’s a tired ol 350. It also isn’t throwing any other codes. I’ve also only driven it about 5 miles since fixing the original code so it may throw one later on. Please help I’m very confused.