Help! Ignition cutting offf?

[BILLS_XLR]

Cubby, Thanks but I don't think that a faulty O2 sensor/connection would effect only the #2 cyl??????
Bruce, Thanks as well. The miss is intermittent, cold or hot but seems more apparent/noticable when warm at idle in gear. It feels and sounds like ignition as there is a complete momentary hic-up (cutoff) not just a stumble. The scan did indicate CYL 2 as the location and with that many events it must also be happening at higher RPM while driving.

 

[Mad_Trbo]

Thread Rejuvination ** Random Miss at idle*** Lean misfire

I am wondering if anyone saw or knows of the resolution to this issue?

I am seeing the same issue but to both banks. I gave the car to the dealership but was not happy with their progress and decided to work on the car myself.

I believe I am experiencing a lean misfire at idle. I cannot detect by seat of pants anything occurring while the car is under load. Every thing I have read online says to check for vacuum leaks, but I can't find any sort of diagram for hose routings or exactly where rubber meets metal.

I am wondering if where the intake tubing along the back of the engine is prone to problems. I would imagine there is a rubber coupling back there, but it doesn't seem easy to access. Any feed back?

 

[rexster314]

P0800 through P0899 Trouble Codes. OBD-II Generic Trouble Codes - [url]www.SmogTips.com. Transmission Trouble Code (Part B). Transmission trouble code and problems. Transmission Clutch Pedal Switch.[/URL]

Seems like the range of codes from P0800 through P0899 are transmission/drive train related

And while looking around found this nifty little webpage. Enter your code you're looking for and "voila"! There's your answer

OBDII diagnostics. Trouble code definition for code P0320

 

[Mad_Trbo]

Closing the loop on my issue Intermittent misfire ***Spark Plug***

I wanted to close the loop on the issue I was facing, intermittent misfire at idle.

First I want to say stay away from Sewell Cadillac on Lemon Street here in Dallas. After specifically telling them I was experiencing an intermittent misfire, I was called and told the car had no issue. I requested they let the car run for a minute and was called back and told they would get to work. Hours later I was told I needed some $500-$600 in vacuum hose repairs that I had a leak which was causing a lean misfire. Once I heard that I decided I had already invested some $20 plus k in an education at NTI, the only thing holding me back was no garage, no technical manuals or diagnostic tool. Before Sewell could rape me I said I'll pay your diagnostic fee and put the rest of the money towards tools and deal with the HOA at my condo for working on the car in the parking garage.

At any rate after spending Saturday fumbling through the Tech2 and these manuals. I diagnosed a random misfire event first on cylinder 7 and then cylinder 2. Cylinder 7 turned out to have a bad injector plug. The retaining clip was broke and I believe somehow the injector was working itself loose and probably had dirt creating and issue. I replaced that and now only a misfire on cylinder 2. Decided to pull the plug and what you see below is what I had. Replaced the plug and after a good 40 minute drive in the city no 2 no longer misfires. Now I just need to determine what is causing the plug to ash up like that. Do I have a problem cylinder bad gas or what. The other plugs did not look the same...

Anyway hopefully this information will be useful to others who come after me looking for answers.

Damn vacuum hoses, get the f out of here with that ish......

 

[Stella]

If you had a vacuum leak it would affect all the cylinders. To check you can start the car hood up then go around the suspected area and spray starting fluid. If the engine revs you've found a leak. The vacuum will pull the starting fluid in and rev the engine.
As for the plugs. Have they ever been replaced? If those cylinders were running long as described the plugs could be fouled who knows. Good time to replace all eight and check on them after some miles. That will give you a better idea. Plug looks white on the lean side to me. Just as long as you don't see metal flaking or oil your good

 

[Mad_Trbo]

Exactly

Exactly what I explained to the service adviser, vacuum would impact both banks.

I changed out all eight, I have a feeling I still may have a borderline injector issue on number two. I am somewhat annoyed because I keep getting an voltage out of range error when I try to perform the injector balance test.

If you had a vacuum leak it would affect all the cylinders. To check you can start the car hood up then go around the suspected area and spray starting fluid. If the engine revs you've found a leak. The vacuum will pull the starting fluid in and rev the engine.
As for the plugs. Have they ever been replaced? If those cylinders were running long as described the plugs could be fouled who knows. Good time to replace all eight and check on them after some miles. That will give you a better idea. Plug looks white on the lean side to me. Just as long as you don't see metal flaking or oil your good

 

[pure zen]

What's in your wallet?

Mad,,,, Thanks for the informative post on your misfire issues.

$600 vacuum line hose replacements? That stuff is dirt cheap per foot. They must have been planning to use s/steel reinforcement around the hoses, lol

Good decision to tackle that problem yourself....

p z

 

[onalaska]

Vacuum Leaks

Did you try tightening up the intake manifold bolts? The normally aspirated Northstar is famous for the bolts loosening due to the plastic intake manifold compressing and allowing air to bypass into individual cylinders which would not exhibit the same problem as a bad or loose vacuum hose. It's particularly noticeable during idle. Just tightening the bolts may cure the problem.

 

[richardyoo]

Another thing you could do while you wait to check on the plugs is to move the #2 injector to a different location. this way you can see if the problem with the plug is localized to cyl 2, or if it moves due to the relocated injector.... this would help you eliminate the possibility of a questionable injector as well

Good luck

(BTW - I gave up on the dealers too - they don't have the time or patience to do true troubleshooting...)

 

[Mad_Trbo]

Process of elimination

Thanks for the suggestions.

I looked into the intake bolts or supercharger bolts and did not detect any looseness. I don't think the V suffers from the same intake issues as the naturally aspirated.

Richard

When it comes to moving things around, I take the simplest and least expensive approach first when diagnosing. I did not move the injector, I am not super familiar with how this engine comes apart and goes together. But it looked like a real PITA to get the fuel rail off to move the injector. This is why the injector balancing test was so appealing to me. I still haven't figured out why that test won't work from the Tech 2. It seems I need to buy another piece of equipment.

I am no longer experiencing the miss issue I had before so I've stopped working on that. Other things to look into now.

Thanks again for the post

 

[BusaMan]

FWIW, I've seen bad gas make the engine intermittently die from idle; e.g., small amount of water in the gas. Try running a shot of STA-BIL or Gumout Gas Treatment through it.

Tim

Thanks for the suggestions.

I looked into the intake bolts or supercharger bolts and did not detect any looseness. I don't think the V suffers from the same intake issues as the naturally aspirated.

Richard

When it comes to moving things around, I take the simplest and least expensive approach first when diagnosing. I did not move the injector, I am not super familiar with how this engine comes apart and goes together. But it looked like a real PITA to get the fuel rail off to move the injector. This is why the injector balancing test was so appealing to me. I still haven't figured out why that test won't work from the Tech 2. It seems I need to buy another piece of equipment.

I am no longer experiencing the miss issue I had before so I've stopped working on that. Other things to look into now.

Thanks again for the post

 

[Agitated Monkey]

This is a guess. I would suspect the oil in air filters as mentioned and the E3 plugs. North stars don't seem to like improved plugs. I put a set of Bosh Platnums in another Northstar thinking of prevention and improved performance. The result was misfire at random times and I took it to Cadillac Expert who educated me on the finicky Northstar put factor AC in and problem went away.