Cruise miss/surge, timing varies

[ThikStik]

Its when Im barely on pedal, and very inconsistant. Sometimes it feels like a dead miss when tcc is on at around 45 mph. It also does it at off idle on up in neutral. Acts fine under load. I decided that it must be timing variations, and put a light on it. When car missis, the timing light goes out real quick and you can see damper advance for an instant. Recent wires,plugs, coil,module,crank sensor. I thought I had nailed problem when I looked into the sensor gap in the cam sensor. Sure enough, there was a tine peice of metal from the breaker plate's tab. I figured it was reusable since the breaker plate stays tightly on the shaft. So I just removed that metal , it was as tiny as a piece of sand. Car ran better...but its back to doing it. I dis-connected cam sensor, and it acted better for a few seconds, then went back to missing. Since the damper does show a timing advance that is comminsurate with the miss, it sounds like an ign problem...what do you guys think? Thanks

 

[Mikemill]

I have the exact same problem with my GN hopefully somebody has some helpful tips. Mine runs fine under boost (20lbs.).

Mike

 

[ThikStik]

Mike
Have you tried looking at timing during the miss? People here say the crank sensor is bad or it isnt. I have seen them act marginal. Also , the cam sensor has that same reputation, but I say it can be marginal also.
I have seen marginal crank sensors that will cause big swings intiming. But since our cars have these one off cam sensors, I havent got anything to compare them to. As mentioned, I removed a tiny piece of metal from within the openings in my cam sensor cap, and it seems problem was only better, but not fixed.
cya

 

[ThikStik]

Oh yea, mine is fine under boost also. There are times when it seems it would like to stall after a hard decel to a stop, but totally inconsistent.

 

[Mikemill]

No i haven't tried the timing light, and actually i have not had a chance to do much troubleshooting.

Mike

 

[Brian Mc]

just chiming in with the exact same problem. It's been like this since i bought the car, in 2002

 

[VadersV6]

I had major coughing and sputtering right off idle when I got mine. Cant really say what it was that fixed it, cause I had to do so many things before it improved. The main issue was vacuum leaks, everywhere. I replaced all the hoses and clamps, pulled off the EGR cause it was cross talking between ports, replaced the fuel injectors cause the O-rings were badly damaged and causing a HUGE vacuum leak. I also pulled the intake off and changed the gaskets. Whoever did it before should have been shot. It was a really bad job that looked like it had been leaking. Another thing that contributed was a loose crank sensor, banging around. Also, just go get a new cam sensor. I was able to rebuild mine with my own shims and wave washers, and mods to the bushings to allow oiling, etc etc. But it would be much easier to just buy a new one, given the prices that are out there right now. Also do a search on cam sensor adjustment, with my handle in the user name box. There is a shortcut for installing the cam sensor, that the engineers came up with and designed into the sensor itself with various markings. You dont need a voltmeter or any special tool.
What are your BLM's?

 

[ThikStik]

Yea, I maintenanced my cam sensor . In other words took it apart and cleaned/oiled it like can be done on HEI distributors when they hang up. There is no excessive wear. If anything is wrong, I think it would be in the cap where the hall-effect swithc is. Getting a new one is good advice...on this car ther'es nothing left that hasnt been adressed. I do have the Casper's tool, so my setting should be on. Ill look at blm's, but I think they are very close to 128. I do have a blocked off egr while still running a Testa chip that was set for egr, but this problem shows up sporadically and in times of 0% egr duty cycles. Like in neutral....but dont get me wrong, its only an intermittant miss then. The strong miss is at 45 mph with tcc in and very slight pedal. And this is only sometimes. Any more pedal and its gone.