# New problem?



## #1DEER 1-I (Sep 10, 2007)

My 03 S10 has a rough idle and the check engine light is on and blinks. The code is P0301 which is misfiring cylinder 1. I replaced the plugs and wires and the distributor cap. It still runs bad, and has a rich smell while running. Any ideas?


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## #1DEER 1-I (Sep 10, 2007)

I just noticed the autoparts store gave me the wrong part number instead of 41-993, they gave me 41-933. The resistor on the wrong one they gave me is 2.5-12--220, and the one that is supposed to be in it is 4-7.5k.


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## Huge29 (Sep 17, 2007)

So, you were given the wrong spark plug? You should really change them all, if that is what you are saying.


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## #1DEER 1-I (Sep 10, 2007)

Huge29 said:


> So, you were given the wrong spark plug? You should really change them all, if that is what you are saying.


Yes I changed all the spark plugs so I guess I'll be doing it again today.


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## swbuckmaster (Sep 14, 2007)

Just hope the plugs they gave you didnt damage the pistons.


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## #1DEER 1-I (Sep 10, 2007)

Running a little better with the right plugs still not running right though. Putters still at idle, and smells like it's running really rich. Would you guess a vaccum leak? The spider ? Intake leak?


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## Fowlmouth (Oct 4, 2008)

http://www.s10forum.com/forum/f107/dreaded-misfire-p0301-2k-s10-4-3-a-475847/

My guess would be the spider injector on #1...................


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## stuckduck (Jan 31, 2008)

What engine? 4.3 or 2.2? If you say it smells rich and I would check for a leaking fuel pressure regulator. on a 2.2 it's on the fuel rail. Connected with a vacuum hose. They leak fuel into the manifold. Usually will set a rich code but sometimes will set misfire. If it's a 4.3 than get a mirror and open the throttle plates and have some one turn the key on to prime the system. Then look down in the air plentum to see if you see fuel dropping out of the regulator. Also you can hook a fuel gauge to it to see if fuel pressure will stay steady after key is cycled and fuel system is primed. If it falls fast than you either have a leak at the regulator or a bad check valve in the pump. Does it have a extended crank time? I have also seen a plugged cat cause misfire codes on one bank. Lots to check before you start throwing parts at it.


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## #1DEER 1-I (Sep 10, 2007)

stuckduck said:


> What engine? 4.3 or 2.2? If you say it smells rich and I would check for a leaking fuel pressure regulator. on a 2.2 it's on the fuel rail. Connected with a vacuum hose. They leak fuel into the manifold. Usually will set a rich code but sometimes will set misfire. If it's a 4.3 than get a mirror and open the throttle plates and have some one turn the key on to prime the system. Then look down in the air plentum to see if you see fuel dropping out of the regulator. Also you can hook a fuel gauge to it to see if fuel pressure will stay steady after key is cycled and fuel system is primed. If it falls fast than you either have a leak at the regulator or a bad check valve in the pump. Does it have a extended crank time? I have also seen a plugged cat cause misfire codes on one bank. Lots to check before you start throwing parts at it.


It's the 4.3 liter. No rich code has been set just P0301 which is cylinder 1 misfire. Cylinder ones brand new spark plug smells bad of fuel and has turned pretty black with the truck not running much . It seems like it is giving off a more white smoke out of the tailpipe and the exhaust smells a lot like gas. The truck has 175,000 miles on it. As for the fuel pressure test, when I would turn the key on it would raise and then fall once it reached it's peak . It has a brand new fuel pump less than 6 months old, and I've had fuel pumps go bad before this shakes the truck pretty bad and has a bad exhaust smell. Yes it takes extended crank time and applied gas even sometimes to get it to start . The first start of the day it usually starts easier.


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## stuckduck (Jan 31, 2008)

Check the fuel pressure regulator.


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## martymcfly73 (Sep 17, 2007)

What does the exhaust taste like? Run a hose from the exhaust to the cab and duct tape the cracks so it's airtight. Then run the motor at Hugh idle for 2-3 hours. If it tastes sweet it's the plugs, if it's bitter try suck starting it. But use lip balm I hear the Chevy's exhaust get hot. I recommend carmex.


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## Huge29 (Sep 17, 2007)

The shaking = fuel pressure regulator; it is getting too much gas dumped in. Eventually it will shut right off and won't restart for a while until the fuel leaks down into the crankcase, correct?


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## #1DEER 1-I (Sep 10, 2007)

Huge29 said:


> The shaking = fuel pressure regulator; it is getting too much gas dumped in. Eventually it will shut right off and won't restart for a while until the fuel leaks down into the crankcase, correct?


I haven't taken it very far really. But it hasn't ever quite yet or not started for me. After it's been started and ran it takes more cranking to get it started, but it still starts .


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## brookieguy1 (Oct 14, 2008)

martymcfly73 said:


> What does the exhaust taste like? Run a hose from the exhaust to the cab and duct tape the cracks so it's airtight. Then run the motor at Hugh idle for 2-3 hours. If it tastes sweet it's the plugs, if it's bitter try suck starting it. But use lip balm I hear the Chevy's exhaust get hot. I recommend carmex.


McFly, I like you and most your posts, but never, and I mean NEVER....badmouth a Chevy.;-)


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## martymcfly73 (Sep 17, 2007)

brookieguy1 said:


> McFly, I like you and most your posts, but never, and I mean NEVER....badmouth a Chevy.;-)


Iife long Dodge people don't understand the live affair with Chevy.


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## brookieguy1 (Oct 14, 2008)

martymcfly73 said:


> Iife long Dodge people don't understand the live affair with Chevy.


I understand. I heard there's still a few of you around.:grin:


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## #1DEER 1-I (Sep 10, 2007)

Well it's not the spider injector or fuel pressure regulator.


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## CROC (Sep 12, 2007)

stuckduck said:


> Check the fuel pressure regulator.


I second this its common.


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## CROC (Sep 12, 2007)

A misfire is usually caused by the lack any of these 3 things. you need to check compression, spark and fuel. If you are sure you have spark and fuel, check compression.


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## #1DEER 1-I (Sep 10, 2007)

CROC said:


> A misfire is usually caused by the lack any of these 3 things. you need to check compression, spark and fuel. If you are sure you have spark and fuel, check compression.


Brand new plugs and wires: $110, New Spider/regulator $370, at 175,000 miles I don't feel to bad having these replaced. I did a pressure check on cylinder 1, it seemed good and didn't seem to have a gasket leak on the head. I haven't checked the intake manifold yet. But with the price of things and the amount of tear down it's be nice to get it right this time.


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## stuckduck (Jan 31, 2008)

#1DEER 1-I said:


> Brand new plugs and wires: $110, New Spider/regulator $370, at 175,000 miles I don't feel to bad having these replaced. I did a pressure check on cylinder 1, it seemed good and didn't seem to have a gasket leak on the head. I haven't checked the intake manifold yet. But with the price of things and the amount of tear down it's be nice to get it right this time.


Take it to a shop and have it diagnosed! Your throwing parts at it that it doesn't need. You could have a valve issue, and here you are putting parts on it it might not need. I have seen MANY people try this approach. If they would have taken it to a reputable shop just for diagnosis they would have come out ahead. Trust me!


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## #1DEER 1-I (Sep 10, 2007)

stuckduck said:


> Take it to a shop and have it diagnosed! Your throwing parts at it that it doesn't need. You could have a valve issue, and here you are putting parts on it it might not need. I have seen MANY people try this approach. If they would have taken it to a reputable shop just for diagnosis they would have come out ahead. Trust me!


I'm working with someone on it right now who's mechaniced their whole life . They've worked on big rigs , replaced probably 50 motors , 50 transmission, worked on hundreds of vehicles, and all on there own. The compression check I think was around 155 in the cylinder. The truck runs okay once the engine is revved up past about 2.5 rpm's. Like I said running pretty rich by the smell of the exhaust.


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## #1DEER 1-I (Sep 10, 2007)

Okay so the plugs seem to be firing but they don't really have a good snapping spark. I checked the coil it has great spark. The top of the distributor seems to be a little looser than it should , but would the distributor make sense if only 1 cylinder is misfiring? Took the cover off the top of the cylinders, they all seem to be moving up and down properly while cranking it, and compression sits at around 150 in cylinder 1. I'm at a loss.


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## stuckduck (Jan 31, 2008)

#1DEER 1-I said:


> Okay so the plugs seem to be firing but they don't really have a good snapping spark. I checked the coil it has great spark. The top of the distributor seems to be a little looser than it should , but would the distributor make sense if only 1 cylinder is misfiring? Took the cover off the top of the cylinders, they all seem to be moving up and down properly while cranking it, and compression sits at around 150 in cylinder 1. I'm at a loss.


 You should be getting 30KV at the plug... pressure leak down test? valve train? cranking compression could be ok but running compression could be off. vacuum leak? smoke the engine. what are your fuel trims? long and short? what are they at idle vs cruise at 55mph... like I said take it to a shop pay the diag fee and you will be better off. your still at a guessing state.


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