Ideling problems

I have a 89 S-10 Blazer 4x4
4.3liter TBI
Automatic

I bought this vechile not working and and am now trying to get it to run prpoerly.

Currently it drive decently, but doesnt idel for a sh*t.
I installed new spark plugs, wires, cap and rotor.

After that i thought about checking the timing, I dissconected the wire under the dash, and started it, it barley stayed running chugged real bad then all of a sudden ideled perfectly. Timing was just fine. But after reconnecting the wire and starting the vechile again nothing had changed.

When I am on the gas pedel everything is just fine, but when i let it idel it is very rough and the engine almost shakes from side to side.

I am lost! :banghead:

Can anyone help? PLEASE

Did you time it to zero?

yeh the timing is right on, when the wire under the dask is connected the engine runs really rough and the engine rocks from side to side. But with the wire dissconnected (like you are suppose to to set the timing) it runs really smoothly.
Is it safe to drive the vechile with the wire dissconnected?

yeh the timing is right on, when the wire under the dask is connected the engine runs really rough and the engine rocks from side to side. But with the wire dissconnected (like you are suppose to to set the timing) it runs really smoothly.
Is it safe to drive the vechile with the wire dissconnected?

No, do not drive it like that.

So are you setting it to zero? Is that what the timing is supposed to be for that truck?

Yes the timing is set to zero, and that is where it is suppose to be set, then the computer is suppose to adjust it from there

Have you ever replaced the following:

Air Filter
PCV Valve
Fuel Filter

Have you ever cleaned the following:

IAC Valve
EGR Valve
Throotlebody Butterfly

Also, do you have any check engine light?

i have replaced all of those except the iac valve.

have cleaned up the throotlebody with carb claner

and there is no check engine light

Have you cleaned the IAC valve?

not yet gonna check it tomorrow, but i think i did pull it out once and looked good

i checked the iac valve and cleaned it up al looked good and was in check with what my repair manual said.

After talking to someone, I dont remember exactly what they said something about stuck it closed or open loop or something. But after talking to the I unplugged the electrical connector from my map sensor and the vechile ran great, i then replaced the sensor and reconnected it but did not fix the problem.

I dont remember what they said but something about dissconnecting that sensor and it running fine was suppose to mean something.

Usually will mean there is a vacuum leak.

ok i will start checking those, is there any perticular places that vaccume leaks tend to show up at.

You know any more common places for them

Thanks

Usually at the connections.