Need help 1987 V10

[farmboy2188]

Hey this is my first post, I have a 1987 Gmc v10 with the 350 tbi (2.02 heads mild hydraulic  comp cam, dual plane intake) i was driving and when i stopped at a red light and applied throttle it started to knock bad almost like it’s detonating so i went home and did the usual when that happens change fuel filters flush the tank new fuel in with conditioner, make sure all the spark plugs have good spark change the coil and reset the timing to 0* the factory spec, i did all this and it’s still doing it so i made sure all the valves and rockers were in spec and it doesn’t have lifter tick so that’s fine but it starts great, and drives fine until it’s above 1800 rpm under load or you stomp on it so i’m lost what it could be any one have any ideas much appreciated?


Sent from my iPhone using Tapatalk

[JohnnyPopper]

How old are the cap, rotor, and, wires?

[farmboy2188]

The cap rotor and wires have 10,000 km on them tops i replace all that when the motor was done


Sent from my iPhone using Tapatalk

[JohnnyPopper]

Thanks,

You said you checked the plugs- replace them? or examine them?

Did you look under the inside of the cap at the rotor?

The problem sounds electrical to me. Things are calm up to 1800 rpm, or trouncing it. So it loses stability under those conditions.

[farmboy2188]

Yeah the rotor and cap are fine no moisture and anything i think then and the points are clean the plugs are all great no build up or hot spots


Sent from my iPhone using Tapatalk

[bd]

OEM TBI?  Any trouble codes stored?  Have you verified the fuel pressure?  What color is the spark?

[Mike81K10]

Keep in mind that you could have got some bad fuel or a problem with your fuel system could exist.

[JohnnyPopper]

"Yeah the points are clean"


Sent from my iPhone using Tapatalk

That's the problem right there! 

Did you see any tracers on the cap or on top of the rotor?

I think 10 K miles is a good time to do a tune up myself, but hey...