Help. High Rpm Miss. Tried Everything.
03-28-2006, 08:48 PM
#16
Registered User
Join Date: Jul 2002
Location: GA
Posts: 177
Re: Help. High Rpm Miss. Tried Everything.
Hey, hope i can help.... have fixed 3 high rpm misfires now....
96 lt1- loose/broken MAP sensor plug
97 lt1- plug wires
97 lt1- optispark
ANY shop your taking an lt1 to better have someone that KNOWS a scanner.
96 lt1- loose/broken MAP sensor plug
97 lt1- plug wires
97 lt1- optispark
ANY shop your taking an lt1 to better have someone that KNOWS a scanner.
03-29-2006, 10:25 AM
#17
Registered User
Join Date: Nov 1998
Location: St Charles MO, USA
Posts: 575
Re: Help. High Rpm Miss. Tried Everything.
Originally Posted by Shankels94TA
Hey, hope i can help.... have fixed 3 high rpm misfires now....
96 lt1- loose/broken MAP sensor plug
97 lt1- plug wires
97 lt1- optispark
ANY shop your taking an lt1 to better have someone that KNOWS a scanner.
96 lt1- loose/broken MAP sensor plug
97 lt1- plug wires
97 lt1- optispark
ANY shop your taking an lt1 to better have someone that KNOWS a scanner.
03-29-2006, 03:27 PM
#18
Registered User
Join Date: Oct 2003
Location: Chicago burbs
Posts: 618
Re: Help. High Rpm Miss. Tried Everything.
Here's my personal experience with this problem. I replaced the opti with a brand-new GM opti. The car started missing at high RPM two days later(at least that's when I noticed it). I ended up replacing the plugs, wires, coil, fuel filter, everything. It still missed. I then read that many of the brand new optis leave ht efactory with loose rotor screws. I dove in and pulled the cap, only to find that the screws were TIGHT.
I went ahead and loctited them anyways, and cleaned the inside of the cap and rotor with electrical contact cleaner. After reassembly I took it for a drive and it didn't miss a beat! It's been about 300 miles now, and it still pulls perfect to 6,400 RPM.
My only guess is that there was some kind of substance inside the new opti that I cleaned off when I had it apart(moisture from sitting for ten years maybe??). Nothing else was changed.
I went ahead and loctited them anyways, and cleaned the inside of the cap and rotor with electrical contact cleaner. After reassembly I took it for a drive and it didn't miss a beat! It's been about 300 miles now, and it still pulls perfect to 6,400 RPM.
My only guess is that there was some kind of substance inside the new opti that I cleaned off when I had it apart(moisture from sitting for ten years maybe??). Nothing else was changed.
03-29-2006, 03:58 PM
#19
Registered User
Join Date: Mar 2003
Location: Maryland
Posts: 1,147
Re: Help. High Rpm Miss. Tried Everything.
Originally Posted by izzyz28
Here's my personal experience with this problem. I replaced the opti with a brand-new GM opti. The car started missing at high RPM two days later(at least that's when I noticed it). I ended up replacing the plugs, wires, coil, fuel filter, everything. It still missed. I then read that many of the brand new optis leave ht efactory with loose rotor screws. I dove in and pulled the cap, only to find that the screws were TIGHT.
I went ahead and loctited them anyways, and cleaned the inside of the cap and rotor with electrical contact cleaner. After reassembly I took it for a drive and it didn't miss a beat! It's been about 300 miles now, and it still pulls perfect to 6,400 RPM.
My only guess is that there was some kind of substance inside the new opti that I cleaned off when I had it apart(moisture from sitting for ten years maybe??). Nothing else was changed.
I went ahead and loctited them anyways, and cleaned the inside of the cap and rotor with electrical contact cleaner. After reassembly I took it for a drive and it didn't miss a beat! It's been about 300 miles now, and it still pulls perfect to 6,400 RPM.
My only guess is that there was some kind of substance inside the new opti that I cleaned off when I had it apart(moisture from sitting for ten years maybe??). Nothing else was changed.
Or maybe one or more of the wires where lose on the opti
Thanks for your input tho!
04-06-2006, 04:35 PM
#21
Registered User
Thread Starter
Join Date: Apr 2000
Location: Austin, TX or Texas State University at San Marcos
Posts: 1,070
Re: Help. High Rpm Miss. Tried Everything.
Shop is taking FOREVER!!!!!!!!!!!!!!!!!! But they are supposed to test drive it first thing friday morning and tell me if changing the valvesprings fixed it... Cross your fingers for me!!!
04-06-2006, 04:53 PM
#22
Registered User
Join Date: May 2003
Posts: 192
Re: Help. High Rpm Miss. Tried Everything.
I solved my intermittent 6K+ miss (LE2 heads, cam) by replacing the MAF sensor. Never saw a code or could see it through data logging. My research revealed that a failing MAF can be tricky to diagnose.
Once I replaced the MAF sensor the miss has disappeared.
Once I replaced the MAF sensor the miss has disappeared.
04-06-2006, 11:08 PM
#23
Registered User
Thread Starter
Join Date: Apr 2000
Location: Austin, TX or Texas State University at San Marcos
Posts: 1,070
Re: Help. High Rpm Miss. Tried Everything.
FIXED!!!!!!!!!!!!!!!!!!
It turned out to be valve float. Put the beehives in and BAM! High RPM miss is GONE!!!
It turned out to be valve float. Put the beehives in and BAM! High RPM miss is GONE!!!
04-07-2006, 07:16 AM
#24
Registered User
Join Date: Nov 1998
Location: St Charles MO, USA
Posts: 575
Re: Help. High Rpm Miss. Tried Everything.
Originally Posted by 95z28 -quicksilver
FIXED!!!!!!!!!!!!!!!!!!
It turned out to be valve float. Put the beehives in and BAM! High RPM miss is GONE!!!
It turned out to be valve float. Put the beehives in and BAM! High RPM miss is GONE!!!
04-07-2006, 12:33 PM
#26
Registered User
Join Date: Oct 2003
Location: Chicago burbs
Posts: 618
Re: Help. High Rpm Miss. Tried Everything.
Originally Posted by 97formula1234
Or maybe one or more of the wires where lose on the opti
Thanks for your input tho!
Thanks for your input tho!
04-10-2006, 11:17 PM
#27
Registered User
Thread Starter
Join Date: Apr 2000
Location: Austin, TX or Texas State University at San Marcos
Posts: 1,070
Re: Help. High Rpm Miss. Tried Everything.
NOT FIXED!!!!!!!!!!!!! Car worked fine for 2 or 3 days and now it is doing it again..... 30# SVO's on the way.
04-10-2006, 11:24 PM
#28
Registered User
Join Date: Jun 2005
Location: Atlanta, GA
Posts: 274
Re: Help. High Rpm Miss. Tried Everything.
My car has a miss above 5600 rpm. I'm kinda broke and can't afford to replace all the parts like you are doing so I just programmed it to shift at 5600. I have an auto though and that's still kind of a ****ty solution.
Last edited by infinitebird; 04-10-2006 at 11:26 PM.
