1993 GMC 5.7 TBI Strange Idle/Driveability Problems

[TylerZ281500]

93 disconnect is right at the firewall under the distribution block.

 

[93SierraZ71]

Thanks 4 reply. OK. 12dgs bit much. It should run strong at 4 dgs. 6 is OK too. That yr motor has a couple of disconnects before u get to set timing. Also did u check for chain stretch. Anyway ,how's it run now?

Okay, when I replaced the distributor (because it was running like crap) I found the timing was at 12 degrees adv, so that's when I put it back to 0 degrees. This was like a year ago, still runs like crap now. Also when you put your foot into it, there is a major vibration and shaking, goes away as soon as you let off. Only happens in drive going down the road.

 

[Johnbalderas90k1500]

Did you ever get it figured out.

 

[93SierraZ71]

Well I fixed the vibration, there was a spark plug wire that got melted by the manifold. It's running fine now that it's cold. After Christmas I am going to get a new computer for it and I'll check that knock sensor when I get time.

 

[93SierraZ71]

I FINALLY FIXED IT! Decided to look into the MAP sensor again, unplugged it and the truck ran better, but was very rich obviously. Then I took a closer look at the vacuum line from the throttle body to the sensor, and found it was a thread away from being broken in half. I taped it up for now as all auto parts stores are closed for holidays, now just have to put timing back to where it should be and it should be all good. I'm glad to have her back to normal.

 

[93SierraZ71]

Well I still have a problem, but I bought another truck so this old girl can have a little break till it gets a new motor and tranny. Might mess around with it some more too.

 

[vic_v8]

when is the last time you disconnected the battery and let it sit for a few minutes?

 

[93SierraZ71]

when is the last time you disconnected the battery and let it sit for a few minutes?

I don't know, probably over a year...