87 GN intermittently “skipping””

Cape Cod GN

Member
Joined
May 21, 2014
Hey all, my 87 GN bucks and feels like it’s skipping for a few seconds then runs fine. At WOT it will almost feels like a misfire and sometimes cruising it will skip and “buck” lightly. Here are my scantool readings at idle and warmed up:
MAF: 4
LV8: 27
Volts:13.0
BLM: 142
Speed: 0
Coolant: 190.8
Air Temp:121.1
RPM: 850
TPS: 42
IAC: 25
O2 CC: 1

I was wondering if the O2 CC is to blame? I have read different posts that it should be between 1-250 fluctuations and others say readings at idle from 700-800.
Also looks like my BLMs are high at idle when I go WOT they drop to the 120’s.
Anyone have any ideas on diagnosis from their experiences with these symptoms.
Thanks.
 

TexasT

Texas, Where are you from
Joined
Sep 10, 2002
The cc is the o2 passing 450 on the way up and the way down. Should be steadily counting. The int is missing. BLM is way high. The o2 should be moving around as you drive, but when at wit and accelerating you want 750 or so. Some run less but that is lean and you are playing with fire.
 

Cape Cod GN

Member
Joined
May 21, 2014
The cc is the o2 passing 450 on the way up and the way down. Should be steadily counting. The int is missing. BLM is way high. The o2 should be moving around as you drive, but when at wit and accelerating you want 750 or so. Some run less but that is lean and you are playing with fire.
Thx for that info TexasT.
 

John Larkin

Sublime Master of Turbology
Joined
May 25, 2001
Second thought, my balancer was actually loose once and the crank sensor was losing contact intermittently. It is an infrequent but not uncommon issue. It has to be torqued to 220-ish lb-ft. And you have to remove the intercooler and intercooler fan to get to it. You can put a small pry bar behind it without removing anything and see if it has any wobble. Worth a check.
 

dynoman

Well-Known Member
Joined
Nov 30, 2009
Does it do it only when in boost ? What spark plugs ?
Non resistor plugs have been known to do what you describe , it happened to me .
 
Top