idle misfire

[jayb903]

I'm trying to track down this udle misfire. So far I have ruled out cas, plug, wires, coil, pt, mas, and I just did the egr blocked off. So I'm wondering should I just go ahead and do the 1g cas swap as to get rid of the crank sensor? Because I'm getting close to solving this problem and I'm wondering if this is a better option than buying a 2g cps.

 

[jayb903]

Anyone got any suggestions? Or personal experience?

 

[Dsmj89]

Fouled spark plugs ? Clogged fuel filter ?

 

[TrevorS]

I'm trying to track down this udle misfire. So far I have ruled out cas, plug, wires, coil, pt, mas, and I just did the egr blocked off. So I'm wondering should I just go ahead and do the 1g cas swap as to get rid of the crank sensor? Because I'm getting close to solving this problem and I'm wondering if this is a better option than buying a 2g cps.

I would first think in terms of the plugs (gap and condition) and timing. However, it could also be an injector issue. Have you tried cleaning your TB, using a gasoline additive, performing an intake clean out? Does it only miss at idle, or at other times as well?

 

[jayb903]

I would first think in terms of the plugs (gap and condition) and timing. However, it could also be an injector issue. Have you tried cleaning your TB, using a gasoline additive, performing an intake clean out? Does it only miss at idle, or at other times as well?

It misses throughout the rpm band. I'm going to get another new set of plugs(I've already tried two different sets). My timing is fine(checked yesterday) and I heard misfire is measured from the crank sensor. So I'm thinking along the lines of the sensor because I pretty much ruled out everything else.

But on the other hand I changed my plugs to the "NGK BPR6EKN" the misfire code(p0300) never came up, yet it sounded worse than when I had my NGK BPR7ES in. But when I put the BPR7ES in, the misfire code came up again. In both cases the misfire is there.

 

[92rsAWD4me]

my misfire issue turned out to be a dirty tb and the ports going to the egr. Although if its blocked off I'm not sure this would cause the problem. Also a vacuum/boost leak could cause issue like this so maybe try a boost leak test. But like I said when my stuff was really dirty I got it cleaned out really good all the misfire and rough idle issues went away.

 

[Calan]

I doubt if it's the plugs themselves if you've tried 2-3 sets.

What gap are they set to? .028" is recommended and works for most people. You could be blowing out the spark or something.

What do they look like (burning hot, fouled, etc.)?

 

[jayb903]

my misfire issue turned out to be a dirty tb and the ports going to the egr. Although if its blocked off I'm not sure this would cause the problem. Also a vacuum/boost leak could cause issue like this so maybe try a boost leak test. But like I said when my stuff was really dirty I got it cleaned out really good all the misfire and rough idle issues went away.

I could clean out my TB. My BLT showed nothing leaking, but I guess I could seafoam it and see what happens...

I doubt if it's the plugs themselves if you've tried 2-3 sets.

What gap are they set to? .028" is recommended and works for most people. You could be blowing out the spark or something.

What do they look like (burning hot, fouled, etc.)?

I've tried everything from .25 to .30 between the two plugs. The tips are white but I think thats natural with DSM's. I'm going to buy another set regardless.

 

[rush2252]

hate to bring up CW but one of the symptoms is random intermittent misfiring and eventually the car will cease to run. The crank begins to eat into the Crank Position Sensor and over time will kill it.

Not saying you have CW but your rolling the 99 you could always pull the timing cover and visually inspect.

Kolby

 

[jayb903]

hate to bring up CW but one of the symptoms is random intermittent misfiring and eventually the car will cease to run. The crank begins to eat into the Crank Position Sensor and over time will kill it.

Not saying you have CW but your rolling the 99 you could always pull the timing cover and visually inspect.

Kolby

I also considered that this might be causing this misfire craziness

I'm going to double check everything again above the crank sensor and make sure its none of the other things that cause misfire

 

[rush2252]

I have also had a similar issue it ended up being the lead wire to the coil packs. Follow the triangle connector where it attaches to the coil. It uses a nut and lockwasher with an eyelet on the wire end. Sometimes these rattle loose and will cause one to run goofy.

I had an intermittent misfire problem and this was the issue although mine usually happened running down the road.


Good Luck
Kolby

 

[jayb903]

I have also had a similar issue it ended up being the lead wire to the coil packs. Follow the triangle connector where it attaches to the coil. It uses a nut and lockwasher with an eyelet on the wire end. Sometimes these rattle loose and will cause one to run goofy.

I had an intermittent misfire problem and this was the issue although mine usually happened running down the road.


Good Luck
Kolby

I know its not the coil or pt because I just finished testing both and switched them out with brand new ones from the dealership

Thanks for wishing me luck because I could use some right about now

 

[lacroixdp]

hate to bring up CW but one of the symptoms is random intermittent misfiring and eventually the car will cease to run. The crank begins to eat into the Crank Position Sensor and over time will kill it.

Not saying you have CW but your rolling the 99 you could always pull the timing cover and visually inspect.

Kolby

With the floating thrust bearing in your engine, I can almost guarantee you it isn't crankwalk. You said you ruled out wires - did you rule them out with a visual inspection, or did you replace them with NGKs?

 

[jayb903]

With the floating thrust bearing in your engine, I can almost guarantee you it isn't crankwalk. You said you ruled out wires - did you rule them out with a visual inspection, or did you replace them with NGKs?

I replaced them with some magnecor's and the stock ones are fine(at least visually) I'm going to try an switch them out again today. Does any one have a link on how to test the crank sensor on a 99?