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have a 03 van with a 4.2 . it idles fine lacks a little power accelarating but when engine winds up to high rpm like over 3000 rpm it starts to make a lot of noise from engine knocking like. no codes has 32 psi fuel pressure new plugs and wires. and only when you floor it and wind it up high does it make the noise otherwise runs fine but has a little less power than the other 2 4.2 vans i have any help thanks
My 4.2 makes a very similar sound when I get on it (merging with traffic, etc...). It sounds awful so I avoid full throttle, just use it when absolutely necessary. I wonder if the noise is generated in the exhaust system...don't know...
does yours have any power? this one has no power accelarating at all and the sounds at high rpm are severe. alot worse than one that just has low octane gas.
Brian, my truck has plenty of power so long as I don't tow anything uphill. Vans are very unaerodynamic and pushing that box thru the atmos is gonna take more power than a truck. You might need to compare you're performance with another van...just an idea.
Achtung
its not just like pinging when you have bad gas it really starts to knock pretty bad but only at full throttle. and lack of power is all the time just taking off it is no where close to as powerful as my other vans
Did you check your harmonic balancer? A bad balancer is about the only way you could have symptoms of ignition timing being off, unless work has been done to the cam timing sensor.
does not smoke or use oil at all. The knocking sounds like a timing thing to me. as I said only does it when at extreme high rpms. and otherwise acxcelaration is just very flat, doesnt want to go. I am gonna check balancer and cam sensor shaft timing when I get a chance. Got the truck used and don't know Its repair history. has 83k on it and My driver said oh it has been like that since we got it. of course we have it 7 months and its first time I drove it and was like this is not right.