HHRCruser

Hi, I have the P0304 code- misfire from cylinder 4. I have tried everything. I have used various grades of fuel, reg. med. and super from various stations because I thought that I may be getting bad fuel or water in the fuel. I have used b12 chem-tool and gum out and RXP additives in various tanks of fuel and it seems to help for a while. I have bought a locking gas cap, also swapped coils from one to another, Checked the plugs, cleaned and tightened the ground wire at the right rear of the cylinder head twice, reseated all relays and fuses under the hood, inspected the harnesses for any rubbing or wear and found none. just when I think I have it licked the mil comes back on and sets the code. Has anyone experienced this and solved it succesfully? I was an auto tech for 15 yrs and have purchased the GM HHR manuals from Michigan and It has me thoroughly stumped. The only thing I can figure is it is some kind of pcm fluke. I am at the point of selling the car even though I love it so much. I bought it used last April so I might have the retro active 5 yr 100,000 mile warranty, but it probably won't cover this.

ChevyMgr

Document ID: 1998023
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#PIP3333A: Cylinder Miss On Left Turns And Cylinder 4 Miss On Right Turns - Possible Fuel Contamination - keywords CEL contaminated controls cylinders gas injector intermittent MIL misfire P0300 P0301 rail rust - (Jul 12, 2007)

Subject: Cylinder 1 Miss on Left Turns and Cylinder 4 Miss on Right Turns - Possible Fuel Contamination


Models: 2004-2008 Chevrolet Aveo

2004-2006 Chevrolet Cavalier
2005-2008 Chevrolet Cobalt, Cobalt SS
2006-2008 Chevrolet HHR
2004-2008 Chevrolet Malibu
2007-2008 Pontiac G5
2006-2008 Pontiac G6
2005-2006 Pontiac Pursuit (Canada Only)
2004-2006 Pontiac Sunfire
2003-2008 Pontiac Vibe, Vibe GT
2003-2008 Saturn Ion, Ion Redline
2007-2008 Saturn Aura, Aura Hybrid
2004-2008 Saturn Vue
2007-2008 Saturn Vue Hybrid
with a 4 Cylinder Engine (RPOs L61, L91, LAT, LE5, LNK, LSJ, LV6, or LXT)
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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
On rare occasions, an intermittent engine misfire may be experienced on cylinder 1 during/following a left turn or on cylinder 4 during/following a right turn. The misfire may / will typically last up to 10 seconds. A SES light and DTCs P0300, P0301, and/or P0304 may also be present if the misfire lasts long enough.

This may be the result of fuel contamination and is more likely to occur on vehicles with a returnless fuel rail because it is easier for fuel contaminates to become trapped in a returnless fuel rail since they do not have a fuel return line that returns fuel back to the fuel tank. As a result, any fuel contaminates that make it to the fuel rail tend to gather over the #1 fuel injector inlet when turning left and tend to gather over the #4 fuel injector inlet when turning right, causing this concern. The cylinder next to the fuel feed line (1 or 4 depending on the model) may also experience some random misfires at idle as contaminates enter the fuel rail from the fuel tank.

Recommendation/Instructions:
If the SI diagnostics do not isolate a cause for this concern, inspect the inside of the fuel rail and/or fuel tank for fuel contamination. If this concern occurs intermittently, it is unlikely that fuel contamination will be found by simply taking a fuel sample from the fuel feed line/fuel pressure test port. Typically, it will be necessary to turn the engine off as the misfire is occurring, carefully remove the fuel rail (while keeping the fuel in the rail), and drain it into a clear container for inspection. If this is not possible due to the intermittent nature of the concern, or if no fuel contamination is found by doing this, it may be necessary to inspect the inside of the fuel tank for fuel contamination.

Notice: The Aveo and Vibe have an access cover under the rear seat so the fuel pump module can be removed for inspection without removing the fuel tank.

If fuel contamination is present, refer to the "Fuel System Cleaning" procedure in SI and clean the inside of the fuel tank, fuel lines, and fuel rail. Once the repairs are complete, advise the customer to only use fuel from high quality, high volume Top Tier filling stations. Repairs made as a result of fuel contamination should not be considered as a warranty repair.

JoeR

Or... a bad injector.

esmarkey

Now why didn't they do this on all vehicles!?

Lucky

I wish they did. it would make life a lot easier

HHRCruser

A return-less fuel rail HMMMMmmmmmmm...... That sounds bad. I bet that's it. Seems that it comes on if I'm starting the car when it's parked on a slope to one side or going uphill now that I think about it. So in these times of economical termoil and roller coaster fuel prices, when some may add water to underground fuel tanks to make up losses and some stations sell little to no super unleaded that eventually goes bad, vehicles with returnless fuel rail systems get a P0304 or the likes.

I was running super only for a long time. then over the last couple of months I've been getting the code. I tried a different station that was in the ghetto (where nobody uses super except me) and that made it run really bad.
Now I'm using regular and adding stp gas treatment and it stays off mostly. I guess I have some moisture trapped in the fuel rail.

That, well, ugh, I hope I don't have to remove and drain the fuel rail every time this happens! That can get old real quick!

cz4me

Recommend a can of SEAFOAM. That stuff works great on kids dirt bikes, my bike, my truck, and even mower and chainsaw. Try it, it works.

More_Torque_More_HP

Here are some things to try other than the 'bad gas' reported above: New spark plug. It could be a hairline crack in the procelin or swap it with a different cylinder and see if the misfire moves with the plug.

Could be a bad coil or possible a bad injector. You can do the same thing as the spark plug to check the coil. Swap the coil and see if the misfire moves with the coil.

When you pulled the plug what did it look like comapred with the other plugs? Wet? Oily?

HHRCruser

Thanks cz4me, Tried the seafoam ($9.00 but cheaper than the dealer w/no warranty)! It seems to have cleared it up! I have ran 1 tank from Texaco and about another 1/2 from exxon, and no mil/p0304! I am going to stay away from kroger fuels. probably walmart and conoco too!!! Thanks allot. I've seen that stuff befor but never used it. I too and now a believer.

HHRCruser

It came baaaaaaaack! OK, since the other stuff... I have already done, I have swapped plugs 1 and 4, replaced all the plugs w/$7.00 ac delco iridium plugs, checked and tested for vacuum leaks, removed and flushed out the fuel rail 3 times, checked the connectors at the coils for voltages and grounds/lows, swapped around the coils again, swapped around injectors... again, checked with a spark tester and got spark, I can hear the injectors ticking just fine, Not to mention I am getting black soot now out the tail pipe. Yesterday I dropped the tank, completely emptied it, took fuel samples from the rail and bottom of tank (after sitting an hour) and found absolutely no water, flushed the fuel line from the rail to the tank w/ isoheet, cleaned out the fuel pump w/ carb cleaner, flushed out the fuel rail again, changed the oil and replaced the air filter, re routed some wires to the a/c compressor checked all grounds, Got a brand new gas can and put pure SHELL TOP TIER APPROVED FUEL BACK IN IT, and filled up at Shell w/super... STILL MISSES WITH A P0304...UGHHH...

Now I am noticing that it seems to start after warm up, but it goes away on a hard left turn. I never get any other code than a P0304, never a P0301 or other code.

The bad thing is I just ran over 36,000 miles. I just had it at the dealer to fix a few things before the warranty was up, and the adviser told me that "that's water in the fuel, or contaminates. It will cost you 300.00 to flush the rail, but it's pretty easy to do." So stupid me... I tried to save 300.00 since I was a technician for 15 years... I just about had it with chevy. I have been a chevy customer since I started driving 30 years now. Right now I own a 1995 and 2001 s10's and this HHR. Here lately I just don't know. The whole reason I bought this was so that I didn't have to spend so much time working on the car! Any new suggestions? Thanks in advance