Beretta.net

OK, I have a '96 Beretta with the 3100 engine with 192k and it has developed a misfire which I cannot pin down. While it is idling it will randomly stumble and recover repeatedly. While driving it will feel like it is misfiring badly around 50-60 mph.

The plugs are new and have been changed twice, the wires have been checked out and are fine. (I replaced them with a new set and the misfire didn't go away) The resistance on the coils checked out ok, all within spec. So I ran a vacuum test and it is kinda low around 18 and dips down to 17 when the engine stumbles.  No vacuum leaks that I can find. Compression checked out ok on all 6 cylinders, all between 210 and 220.

The only code that I keep getting is PO441 which is the Evap Purge flow, so I tried disabling the whole purge system and capping the vacuum lead to the plenum but that made no difference to the misfire/stumble. Would that even have anything to do with it?

So I am stumped, oh yeah I also checked into the fuel rail and that was clean as were all the injectors, no obstructions. Fuel filter is new as of 2 months ago. When you step on the gas it will still run hard so it doesn't seem to be starving for fuel. Anyway I am stumped, anyone know what I might have overlooked or what it mgiht be? Thanks.

(pmiller101 @ Aug. 10 2006,00:45)Q
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EThe only code that I keep getting is PO441 which is the Evap Purge flow, so I tried disabling the whole purge system and capping the vacuum lead to the plenum but that made no difference to the misfire/stumble. Would that even have anything to do with it?
I would think if you disabled this with no change in the end then it must be with this part being faulty.

I am just shooting in the dark though.

I have all the the same problems that you are having and I have done  the samethings except unpluging the whole purge system
whats the purge system and how do I do that..
how do I do that then I can tell you what I find out...
I think that my fuel pump is going bad but not for shore...

dirty egr system, valve?  that purge code... is it the fuel canister purge solenoid?  Just wondering, if this solenoid goes out [on my 3800 it will cause all sorts of "quad driver" problems and car will run like junk] will it drag anything else down with it?

I'm not too familiar with po codes, so I can only shoot from the hip.  Anyone else?

ps, unplugging a solenoid does not good because there is a given resistance [variable too] that the computer needs to see.  Unplugging it would only gaurantee trouble.

I Thank it night just be my fuel pump going out. when I bought the car in Feb the pump was replaced with a make sheft one. They took a pump from another car and made it work I think that its about done. but the car runs great after starting with a little miss.

don't overlook your injectors... perhaps one of your injectors is failing, try ohming it out when cold, run the car until it starts missing badly and ohm them out again