Trucks running werid

[1984 Chevy k20]

So I built this truck when I was 14 with my dad, it has ran great with a couple of hiccups here and there with random stuff, well lately it has started to form this nasty clattering and has been more sluggish then normal, and the part that’s making this hard to pinpoint is it has good oil pressure, and runs good, other then around 3000 rpm tends to start like shaking the truck but above and below that point is find and tends to get worse or better depending on temp of engine

I’m just not sure what’s going on and why it’s being a pain

 

[Ricko1966]

I'd check the flex plate,a cracked flex plate will clatter and the knock sensor will pull timing thinking you have preignition.

 

[fast 99]

I'd check the flex plate,a cracked flex plate will clatter and the knock sensor will pull timing thinking you have preignition.

did 84's have a knock sensor?

 

[Ricko1966]

did 84's have a knock sensor?

If it's a 305 yes IDK about 350 or a 350 swapped in on 305 engine management. They upped the compression on the 305s early 80s and went knock sensor. Unsure what year but by 83 I'm pretty sure. LE9 came out in 81 so I'm thinking 81 would have been first year for knock sensor.

 

[1984 Chevy k20]

It’s all old school carb, hei, and mechanical fuel pump stuff so no factory tbi anything

 

[fast 99]

If it's a 305 IDK about 350 or a 350 swapped in on 305 engine management. They upped the compression on the 305s early 80s and went knock sensor. Unsure what year but by 83 I'm pretty sure.

Interesting, remember 305's having more in the way of emissions. Knock sensor never occurred to me.

 

[1984 Chevy k20]

If it's a 305 yes IDK about 350 or a 350 swapped in on 305 engine management. They upped the compression on the 305s early 80s and went knock sensor. Unsure what year but by 83 I'm pretty sure. LE9 came out in 81 so I'm thinking 81 would have been first year for knock sensor.

Hmmm I didn’t know they had knock sensors in 84, this k20 was the “ camper base “ package so not quite all the gizmos of a camper special but came with a heavier duty frame, a different code 350 and other little things, so I think with it being in a heavier gvw, probably is the reason it didn’t really get any emissions to it, but I could be wrong cause I bought the truck already stripped of all emissions

 

[squaredeal91]

Bad balancer?

 

[Ricko1966]

Okay I get tripped up by not asking year,make,model and engine again. Still could be knock sensor though. Look at the distributor does it have a 4 wire plug going from the distributor, through the firewall to a control unit behind the glove box.

 

[1984 Chevy k20]

Okay I get tripped up by not asking year,make,model and engine again.

Sorry that was my bad for not providing the info

It’s a 1984 Chevy k20 with an “M” code 350 that has since been rebuilt to be a 10:1 compression aluminum headed, flat topped piston small block, still running flat tappet cam and running a 650 cfm avs 2 edelbrock, and if it is relavent at all, it has a 3500 stall ( I know way to big, I was young ) with a slightly built th400

 

[1984 Chevy k20]

Sorry that was my bad for not providing the info

It’s a 1984 Chevy k20 with an “M” code 350 that has since been rebuilt to be a 10:1 compression aluminum headed, flat topped piston small block, still running flat tappet cam and running a 650 cfm avs 2 edelbrock, and if it is relavent at all, it has a 3500 stall ( I know way to big, I was young ) with a slightly built th400

4 bolt main

 

[Ricko1966]

Well rockauto seems to think they had them.

 

[1984 Chevy k20]

Well rockauto seems to think they had them.

Huh, that’s really werid, cause that motor didn’t even come with a knock sensor, let alone any wiring, harness, or anything for that type of thing

 

[Ricko1966]

Sorry that was my bad for not providing the info

It’s a 1984 Chevy k20 with an “M” code 350 that has since been rebuilt to be a 10:1 compression aluminum headed, flat topped piston small block, still running flat tappet cam and running a 650 cfm avs 2 edelbrock, and if it is relavent at all, it has a 3500 stall ( I know way to big, I was young ) with a slightly built th400

M code was low compression 350 HD emissions,so very doubtfully it would have knocknsensor

 

[Ricko1966]

Huh, that’s really werid, cause that motor didn’t even come with a knock sensor, let alone any wiring, harness, or anything for that type of thing

Yea didn't have all the info when I started typing.