Jimmy coughing

[iancro]

Hello I have been using this forum for some time but now just became a member because I can not find the answer I need. Well here it goes I have a 1994 GMC Jimmy Vortec 4.3L TBI it will cough and sputter in most gears and usually when I go to accelerate. I have cleaned the throttle body and the fuel system, changed fuel and air filters, spark plugs are fairly new along with wires, changed cap & rotor a few months ago, and checked to make sure the catalytic converter was not plugged. It only started to do this when I would tow my boat at highway speeds but now it does it all of the time.(especially when it is hot)It idles fine and first gear has no problems. No codes come up for the check engine light. The manual I have for it does not have the same engine option and timing procedure is a little shady. I have a good timing light and I know it should be zero degrees BTD It says to put distributor ignition system in bypass mode and I am not sure of that.I know what to disconnect on a full size but not this Jimmy) Any help would be great.

[amorak]

I have a '92 GMC Sonoma in my family. In order to stop the computer-aided ignition advance, you need to disconnect a wire. I am tryint to remember which it is, but as I recall there is a wire underneath the glove box, and it's yellow with a clip connection. Disconnect that and check timing.

I would check the throttle body injectors myself, or pick up a haynes/chilton manual and follow their troubleshooting... Or visit http://www.autozone.com and go to the vehicle repair section to read free manuals!

[iancro]

Thanks, will try.

[iancro]

It was a beige wire with black stripe by passenger lower firewall. timing was way out so I adjusted and will try it for a trip or two.