Random misfire at high RPMs?
 

1997 Chevy Silverado Z71 350 5.7L V8
K&N drop in. Magnaflow cats. Flowmaster catback.
Getting about 11 MPG at 7200' Best I've ever got was 16.6 purely highway.

Recent full tune up. Wires, plugs, cap, rotor, fuel filter.

When I went to change the cap I noticed where the screw would go in is cracked. It doesn't hold the cap down very well at all. So I guess my question is, is this what could be causing this random misfire at high RPMs?

It doesn't happen all the time, but sometimes when I go to get on the freeway and floor it, it will pop up when I'm in the higher RPMs.

The CEL comes on when it happens, then a few days later it'll turn off. So it's not a huge deal. I would just like to get it fixed, whatever it is.

Any other ideas on what could be causing this?

Attachment 11305

If you need me to clarify anything or go into depth on something just let me know. Thanks!

I don't know if liquid steel would fix that. Replace the distributor. Cap should never be less than snug. I am surprised (you say cap hardley on at all) it will even start

Yeah it starts just fine. Okay and I was doing a little research and someone said they were getting a random misfire from a cracked cap. I suppose that case would be similar to mine.

I'll go have a talk with a Chevy technician soon. Need to ask a few questions.

<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:PunctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <w:DontGrowAutofit/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if gte mso 9]><xml> <w:LatentStyles DefLockedState="false" LatentStyleCount="156"> </w:LatentStyles> </xml><![endif]--><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} </style> <![endif]--> I hope things will go well when you talk with the technician about your truck, Kohen Marzolf. What is the year of your vehicle?

Michelle, Chevrolet Customer Service assisting Louis