View Full Version : Stumbling when warm

11-17-2007, 05:01 PM
My car was driving perfectly; now when warm my vacuum is only 10 and it stumblies very badly up to only 5 lbs boost. Will not idle. Only when warm when cold all is well...20 vacuum and 12 pounds boost. JUst as soon as it warms up then it goes to stumbling mode. I checked with carb cleaner and there appear to be no vacuum leaks. Plug wires are firm in place. Since it starts well I assume it is not the cam sensor.

This just started after I installed a new battery and spun out while accelerating. I'm thinking something jarred lose. What should I check? Perhaps the DIS module or the coil pack or fuel filter? THe MAF?

I bought a code reader can someone tell me where it pugs into the car to get code errors?

Oh year 1991 SC all stock but for KN filter panel.

11-17-2007, 11:42 PM
Does anyone have any ideas?

11-18-2007, 07:42 AM
Does anyone have any ideas?

could be your dis

most people say apply more heat sink compound under it but if its acting up you should just pick one up and then put new compound under it

if its acting up then its been burnt once...

or it could be plugs and wires

few others might have a few other things to try first

11-18-2007, 11:28 AM
I assume if it were plug and wires it would stumble all the time not just after it is warm...Does the DIS do something different when the car is warm as opposed to at startup and when the engine is cold?

11-18-2007, 01:47 PM
Do you get a check engine light?

EEC-IV test connectors near the back of the fenderwell on the passenger side of the engine compartment.

The low vac when warm could just be due to the engine running rough. I would start by checking all the connections. Could be a loose connector causing a problem.

If you have a buddy with an SC in the area, you might try changing out the DIS and see if things improve before you buy one.

11-18-2007, 03:21 PM
Thanks no check engine light...I went to pull and pray and got a used MAF from a Thunderbird--removed the MAF connector and it ran fine...replace the OEM with the junkyard MAF and all works well now...