Rough Idle and acceleration ( Help )
 

Just went to lunch , car was running perfect.
Started it up and now have some surging rough idle and some loss of power with acceleration . Filled up gas tank Saturday and added 3 oz ( as per bottle ) of Lucus gas treatment for valves and cylinders . Driven about 20 miles since filling . Do you think this might cause it or do you think I have other problems ? Fouled plug ?

Help ! :(

Vinnie in Ventura
1989 911 3.2 Silver Anniversary Edt

There are many reasons this could happen. Vacuum leak (maybe a hose split), plug wire to a cr@p, etc, etc. Fuel seems only one of many possibilities.

Can you give more information that may be clues? Does it rev freely or stumble at a certain RPM? Did you drive though a HUGE puddle? Did it pour down rain, etc, etc Does it behave at Wide Open Throttle?

Doug

No Water . Stumbles at beginning acceleration , then stablizes.
Could it be O 2 sensor ?

Vince, Did this happen at all before you last gas fill up? If not you may have gotten a bad tank of gas (A bottle of octane booster will help that).

Need more info though.

Jeff it was surging at idle about a week ago but stopped .
I added Lucas Treatment 2 days ago and now the problem is back and constant .

Vince, There are a number of things that could be causing this but The #1 place to start is the DME relay (Located under the drivers seat, it is a small black relay). Try puting in a new one of these (you should always carry a spare in the glove box).

The second thing I would look at is the Idle Speed Control Valve. It may need to be cleaned.

had a similar problem
 

I had a similar problem for a while which went away at full throttle. idle was bucking and the part throttle response was erratic with a good amount of hesitation. search for the thread i did on the subject entitled (i think) 3.2 Hesitation Problem. It turned out to be a bad injector but I managed to replace much of my ignition system in the process of located the problem.

I suggest the following: DME, then spark plug wires, then plugs (maybe there is one that is fouled), then injectors.

Good Luck

vincenza,

Did you fix the problem? What was the source?