[align=right]Post #23[/align]I bought a '99 360 4x4 in an auction with 123,000 miles. I've put about 3,000 on the truck and put new plugsAP 3923

Well, they fouled again or at least one cylinder and I have a misfire or not firing at all.

Plus, I'm still having to run 93 octane to keep the spark knock from being there.

I haven't changed the coil or the wires I can do that or go with a different plug. Anyone have any ideas??

Plus, I'm getting like 13 mpg. I'd love to improve that. Will a bed cover help?


TIA
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13mpg sounds about right. I put autolites in and after a month or two it acted like it had a slight miss. I put a set of Champions back in and it ran great.

I'd check the pleneum gasket though. Kind of sounds like something it might be to me. That would cause it to ping also.

Is it the original PCM? I'd make sure it hasn't been flashed to have to run premium.

 

A lot of friends asked me if it had a chip in it. So I really don't know if it's the original PCM. Is there a way to tell?

Thanks.

 

I'm with hometheatermanon, the intake manifold and champion spark plugs, but try the champion truck spark plugs-------they work.

 

13mpg is avg. for these trucks. A bed cover will help a little, but how long will it take you to make up for the cost of the cover?

****If you haven't changed your wires yet, I'd suggest that along with a new cap and rotor w/ brass contacts.****

While you are into the truck, it wouldn't take much more to check down the throat of that TB and see if you have an oil buildup. Clean that TB while you are at it to. Checking the plenum and cleaning the TB are not necessarily my suggestions for fixing your problem, but it should be done when you don't know the history of the truck.

 

Thanks guys. The TB looks really oily/dirty. Can I clean in place or do I need to pull it off to clean it? The gasket for the plenum was indeed dry rotted and had a little piece missing.