misfire @ high rpm: PLEASE HELP! Im Lost...
04-24-2013, 11:26 AM
#1
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misfire @ high rpm: PLEASE HELP! Im Lost... ok guys, a couple weeks ago i posted a similar thread.....
I have been getting what feels like misfire @ higher rpm (5000+).
especially from a dig, at high rpm it starts misfiring and then shifts and continues misfiring....
car drives fine around town when not @ WOT..
Some things a just changed but no prevail are:
NEW spark plugs (NGK TR6)
NEW MSD 8.5 Plugs Wires
Cleaned the MAF (was pretty dirty)
Checked Valvetrain & Made sure all were torqued to 22ft/lbs (stock rockers)
My next thing i was thinking was possibly a BAD Coil pack......?
i was gonna switch them with my buddies to see if it runs different......
Any another suggestions??
PLEASE HELP
I have been getting what feels like misfire @ higher rpm (5000+).
especially from a dig, at high rpm it starts misfiring and then shifts and continues misfiring....
car drives fine around town when not @ WOT..
Some things a just changed but no prevail are:
NEW spark plugs (NGK TR6)
NEW MSD 8.5 Plugs Wires
Cleaned the MAF (was pretty dirty)
Checked Valvetrain & Made sure all were torqued to 22ft/lbs (stock rockers)
My next thing i was thinking was possibly a BAD Coil pack......?
i was gonna switch them with my buddies to see if it runs different......
Any another suggestions??
PLEASE HELP
04-24-2013, 11:30 AM
#2
How many miles on your valve springs? They could be getting weak. Are your pushrods OEM or aftermarket? You could have bent pushrods. Also, have you checked air fuel ratio? Your fuel pump may be clogged or getting weak and you could be starving for fuel up high.
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2018 Cadillac Escalade 6.2L A10 Pat G tuned.
LS1,LS2,LS3,LS7,LT1 Custom Camshaft Specialist For custom camshaft help press here.
Custom LSX tuning in person or via email press here.
04-24-2013, 02:25 PM
#3
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The pushrods are single piece aftermarket
I havent yet checked the AFR's
the pump is stock i think...... hmmm
04-24-2013, 02:44 PM
#4
Are you getting a flashing CEL when this happens? Have you checked the codes?
I have had this happen on two different occassions. 1st time it was an ASP harmonic balancer causing WOT/High rpm random misfires. I put the stocker back on (with a new bolt of course) and the car was fine, nothing else changed (ASP did not seem suprised and offered a replacement). The other time it ended up being my MSD wires, however the misfire occurred at part throttle, WOT etc...ended up that I burned two wires
I have had this happen on two different occassions. 1st time it was an ASP harmonic balancer causing WOT/High rpm random misfires. I put the stocker back on (with a new bolt of course) and the car was fine, nothing else changed (ASP did not seem suprised and offered a replacement). The other time it ended up being my MSD wires, however the misfire occurred at part throttle, WOT etc...ended up that I burned two wires
