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View Full Version : 92 Magnum 318 stumble



83Shelby
04-27-2010, 07:31 PM
My truck will fire up,idle and accelerate with little throttle or 1/2 and above perfect.But,under light throttle and speeds above 65 ,just maintaining speed it will stumble like crazy.It does it 75% of the time.As soon as I give it more go or at WOT it is perfect.I've changed plugs,wires,cap,rotor,fuel filter blah-blah.Anyone come across this?

turbovanmanČ
04-27-2010, 07:54 PM
Check the intake gasket for leaks.

If it has an EGR valve, plug the hose going to the valve and if this fix's it, you need a new valve and transducer, they come as a package from Mopar, and usually under $100.

83Shelby
04-27-2010, 08:20 PM
I will do that!

Captain Chaos
04-27-2010, 08:28 PM
Its also like our cars, cycle the key three times and see what codes you get.

turbodaytona87
04-28-2010, 12:31 PM
I'm going to vote for plenum gasket as well. My Grand Cherokee did the same thing, it would run alright every except while cruising it would misfire/ping a lot. It never really showed until the engine started to warm up. It was a great experience towing a car across the state like that :(

Look down the TB and see if oil is pooling. If it does turn out to be the plenum gasket, I would highly recommend buying the aluminum plenum plate from Hughes Engines. The aluminum plate keeps the two pieces from expanding at different rates.

http://www.hughesengines.com/Index/products.php?partid=22220

BadAssPerformance
04-28-2010, 01:33 PM
Check the intake gasket for leaks.

If it has an EGR valve, plug the hose going to the valve and if this fix's it, you need a new valve and transducer, they come as a package from Mopar, and usually under $100.

You mean the hose from the right bank manifold? I used a piece of a Coke can in mine :D

92 5.2L Dakotas rule! :thumb:

turbovanmanČ
04-28-2010, 05:10 PM
You mean the hose from the right bank manifold? I used a piece of a Coke can in mine :D

92 5.2L Dakotas rule! :thumb:

Well you can do it 2 ways, either plug off the source vacuum or the transducer to EGR valve, pick your poison. :thumb:

83Shelby
04-28-2010, 07:50 PM
So you guys think that perhaps the plenum gasket would cause it to do this? I mean sometimes she's as smooth as a babies bottom but that misfire/stumble is happening more,then today it wouldn't do it till about 75mph,then you let off to maintain and it starts.Anyways,all of your advise I will start trying tomorrow,thanks.