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2004 Chevy Impala 3800 vacuum line diagram

My 2004 impala (3800 engine) is misfiring. It was lean and I replaced the O2 sensor but it is now misfiring at 2500 rpm. It misfires regularly when I give it gas. on the open road, it begins misfiring at 35 mph. I replaced the plugs and wires also. I found a vacuum hose that was cracked and replaced it but I wonder if there are others and this could be the cause of the misfire.

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6ya6ya
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Posted on Jan 02, 2017

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SOURCE: I got 96 chevy c2500 pickup, 5.7 vortec, engine

Check your bank 2 plugs for colour (do they look hot like they running hot ). Check you EGR Exhaust Gas Recirculation valve (looks like a 80mm diameter spaceship with a vacuum line to the top of it) If this remains closed the engine runs very hot and causes misfire. Possible causes are EGR not opening are 1) perforated diaphragm 2) encrusted valve stem 3) clogged exhaust gas feed pipe. A quick check for function: run the engine and remove the vacuum tube. The engine note should change as the tube is connected and then disconnected. Also pushing on the underside of the EGR with your fingers to lift the diaphragm to open the valve should also result in change in engine note. If its not working just disassemble the EGR and clean with carb cleaning spray, also clean the exhaust gas feed pipe likewise.

Posted on May 04, 2010

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SOURCE: Engine code: Misfire cylinder 1. Replaced plugs

There should be no built up fuel or oil in cylinder. The fuel will be burned off immediately, and there should have been very little unless you have a leaking injector. The only way oil will enter the cylinder is if you have a mechanical failure like worn rings or leaking valve seals.If after replacing the plugs and wires did not correct all or the skip after the first start up and road test then you have another issue causing the skip

Posted on May 23, 2010

emissionwiz
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SOURCE: have 2004 chevy impala 3.4lt idles rough stalls at stops cel on code reads multiple misfires bank one lean replaced plugs, wires,and all 3 coil packs

Please read the info on this at this LINK

Posted on Jun 14, 2012

Testimonial: "Thank you. Found a leaking fuel pressure regulator leaking into the vacuum line. Replaced it, and engine runs great, idles smooth, but now it will not start when engine is cold. Can you help with this?"

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Cylinder 1 misfire detectedrich or lean air/fuel mixture fuel injecter fault and faulty crank shaft sensor


Wow... Thats a lot of diagnostic codes. First... The cyl #1 misfire will cause the Engine to run rich giving you a rich running engine. Therefore the rich lean code. This misfire on cyl #1 can also throw a crankshaft sensor code as it will slow down engine rpm. I would change the spark plug and ignition coil to cyl#1 and have the codes erased and see if that solves the problem. If not, you then need to persue any codes that may reappear.

Jun 06, 2015 | 1999 Kia Sephia

1 Answer

Check engine light code p2196,p2197, po300 ,304,305,306,p2 ,Im freeking out.


P0300 Random/Multiple Cylinder Misfire Detected P0301 Cylinder 1 Misfire Detected P0302 Cylinder 2 Misfire Detected P0303 Cylinder 3 Misfire Detected P0304 Cylinder 4 Misfire Detected P0305 Cylinder 5 Misfire Detected P0306 Cylinder 6 Misfire Detected P0307 Cylinder 7 Misfire Detected P0308 Cylinder 8 Misfire Detected P0309 Cylinder 9 Misfire Detected P0310 Cylinder 10 Misfire Detected P0311 Cylinder 11 Misfire Detected P0312 Cylinder 12 Misfire Detected P0313 Misfire Detected with Low Fuel P0314 Single Cylinder Misfire (Cylinder not Specified) P0315 Crankshaft Position System Variation Not Learned P0316 Misfire Detected On Startup (First 1000 Revolutions)

Read more at: http://www.obd-codes.com/trouble_codes/
Copyright © OBD-Codes.com
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P2195 O2 Sensor Signal Stuck Lean Bank1 Sensor 1 P2196 O2 Sensor Signal Stuck Rich Bank1 Sensor 1 P2197 O2 Sensor Signal Stuck Lean Bank2 Sensor 1 P2198 O2 Sensor Signal Stuck Rich Bank2 Sensor 1

Read more at: http://www.obd-codes.com/trouble_codes/
Copyright © OBD-Codes.com http://www.obd-codes.com/p0002

May 07, 2015 | 2006 Ford Taurus SEL

1 Answer

Have codes indicating bank 2 running lean(po174,po153,po159) also have codes for misfires on all cylinders. Does the misfire trigger o2 codes or does bad o2 sensor cause misfires?


misfire could cause o2 codes. o2 sensors are measuring the oxygen in the exhaust - if you're sending unburnt fuel through there (like a misfire), it would throw the value way off. if you're getting a 'lean' error, I would first suspect a bad fuel injector. But you are having a misfire on all cylinders... I would then look at the ECU as it may be having issues sending the 'open' signals to the injectors.

Oct 18, 2014 | 2003 Jeep Liberty

1 Answer

Cylinder misfire spark


how many miles on the odometer, mines 95k.
ah a v6, P0306 is #6 misfiring. 2.5L V6
300 is all 6 misfiring.... oops.
it is. for sure.
misfire is cause by many things, only 3 in physics, but many real world. (compression + spark +fuel rates)
i works this easy, way.
i have a full scan tool not just a code reader (near useless it)
i make sure my V6 (I have an 04) holds closed loop at idle and 2500 rpm. i f not , fix that first.
easy, it is. just look, bingo, Open loop, (out of control)
fueling is out of control.
but, first i do that tune up. in the manual, 60k , 120k, 180k, see?
do that first. , spark plugs dont last foreever nor filters.
then i replace both front 02 sensors at 100k miles. there design life.
V6 has 2 front sensors. (rear can , just sit and be ignored)
if it misfires. now, i toss a coin.
compression or fuel pressure.
i can do both in 30min flat but i toss coin lands on fuel.
i check fuel pressure and its.
60psi, fuel regulator is bad,
20psi, same, or bad pump or bad 12vdc to pump, 8v to pump is bad wiring.
one thing that helps is to find out if the engine is running too rich or too lean.
and if there are cracks in the exhuast near the 02 sensors.
i force the EFI rich and lean watching both 02 sensors in my scan tool
to see if i can force them lean or rich.
on the v6, we can introduce air leaks, to the plenum.
this will cause lean, and the o2 most react to my lean forcing
or its dead.
i can force richer, if i suspect lean or 02 shows lean, by
removing the Fuel pump regulator hose (vac) and plugging hose fast.
this causes the FPreg to go to high pressure. max.
causing RICH>
i watch the 02 and see it go rich, if not the 02 is bad or you have exhaust leaks, or dead cylinder causing the 02 to fib.
you have 2 banks, and both banks are running off 1 MAF
so you can look at both 02 sensors (front) B1S1 and B1S2
and see if both react the same. to my forcing's.

i dont think you have 3 bad cops out 6. no.
if any cylinder misfires on bank one, then bank 1 o2 goes nuts
same with the Bank 2. this can aid troubleshooting having 2 banks.
the MAF can not lie for 1 cyclinder nor one bank
the 02s can lie for each bank,
both are key to diagnosis.
let me give an example say
injector 1 leaks.
causing 301s
v6
246
135 left
this is your lay out.
my guess is its not lost compression (no test guess, mostly useless)
not 2 bad cops one on each side will cause 300s
not one bad cop. as other side would be ok.
not one bad injector.
my guess, is fuel pressure is way off.
but///???
or maf running lean (dirty, spary clean it 12inches away not close)
low fuel pressure
too high fuel pressure.

all comments are for engine with 60k mile service done,
60k, 12ok, etc.



Jan 13, 2014 | 2002 Suzuki Grand Vitara

1 Answer

05 navigator codes po012 intake " A " camshaft position over ******** bank 1 po302 random misfire po302 cyl. 2 misfire po303 cly. 3 misfire po304 cyl. 4 misfire po2195 o2 stuck lean bank 1 sensor 1 po2196...


there is nothing wrong with the timing chain position . Just a series of sensors that have gone outside the set parameters so if you check and change each one you will clear the faults.

Jan 03, 2014 | Lincoln Navigator Cars & Trucks

1 Answer

2005 Mazda Tribute P0172 & P2270


Hi Paul, Have you had a fault code relating to the knock sensor? That sensor controls ignition timing which can have a relationship to the fault codes you report? Regards John

Apr 06, 2013 | 2005 Mazda Tribute

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