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Misfire at cold and certain MPH


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MOBowhunter
New User

Dec 9, 2013, 8:56 AM

Post #1 of 8 (1802 views)
Misfire at cold and certain MPH Sign In

2000
Toyota
Corolla CE
1.8L
210,000

I had the car in about a year ago, on my way home from work it just started misfiring almost constantly and was barely drivable. Shop put in new plugs and wires and it fixed the problem. Although, they said there appeared to be an exhaust leak at the manifold and the whole exhaust system needed to be replaced. I knew this but didn't have the money.

Fast forward to this year, in October once the weather started getting cooler I noticed the car was running really rough at cold and if you tried accelerating too quickly the CES light would flash. The CES light has been on for 6+ years, was told it was O2 sensors, those replaced several times and didn't have money for the exhaust, plus the car ran fine so I ignored it.

It was getting worse as the weather got colder.

I ordered new exhaust from the manifold all the way through the muffler. Took everything apart, put all the new stuff in. My power has probably increased a good 30-40%...VERY noticable. However, the core problem is still there periodically.

If you start the car cold and try to drive before the water temp has come up, you'll get a misfire on Cylinder 4 and sometimes Cylinder 1. If you let the car come all the way up to warm, the CEC light will sometimes come on during driving with the same code (C1 or C4 misfire) but you don't notice anything with the car when that happens.

The only other time you know something is wrong with the car is at 45mph just cruising at that speed you can feel the engine misfire and "jump" and the light will come on for a misfire. If you stop and just let it idle, you'll feel a periodic misfire but not nearly as rough when cold.

Unfortunately the car also uses oil. Probably 1 quart of oil every 1,000 miles but I keep it topped off.

Should I go straight to doing a pressure test? Swap injectors and see if the problem follow the injector or the cylinder?

Seems odd to me that it runs so much better when warm, but then still not quite right at idle or for whatever reason 45mph.
Cruising at 65-75mph on the interstate and it runs just fine like there is no problem whatsoever. If I clear the codes after the car has warmed up, and go drive on the interstate, I can drive all day and not get a misfire but settle down to 45 mph and it'll misfire and 90% of the time it's cylinder 4.


GC
User
GC profile image

Dec 9, 2013, 9:11 AM

Post #2 of 8 (1787 views)
Re: Misfire at cold and certain MPH Sign In

Need to get the codes read to know what codes are currently stored. A helpful check would be to pull the plugs and have a look at them since its pretty easy on this engine. Post code #s here.


____________________________________________________
Willing to help, willing to learn... Rob


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Dec 9, 2013, 9:15 AM

Post #3 of 8 (1785 views)
Re: Misfire at cold and certain MPH Sign In

OK - Yes I'd do a compression test with the symptoms. Chance that the two cylinders you've found are lower or out of spec. Perhaps cylinder wall wash from misfiring so long and not good to ignore that check engine icon ever never mind 6 years!

Cat/conv must have been real trashed as well and O2 sensors.

Quick look showed coil on plug design. IDK, swap around if compression is good and see if problem follows or get a pro diagnosis before you trash another converter,

T



MOBowhunter
New User

Dec 9, 2013, 9:16 AM

Post #4 of 8 (1782 views)
Re: Misfire at cold and certain MPH Sign In

Right now I'm mostly just getting
P0304 - Cylinder 4 misfire detected

and maybe once in 10 times it's
P0301 - Cylinder 1 misfire detected

before changing the exhaust I was also getting
P0420 - catalyst system below theshold
P0171 - too lean bank 1
P0300 - random misfire
P0301 - misfire cylinder 1
P0302 - misfire cylinder 2
P0303 - misfire cylinder 3
P0304 - misfire cylinder 4


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Dec 9, 2013, 10:13 AM

Post #5 of 8 (1761 views)
Re: Misfire at cold and certain MPH Sign In

With that kind of mileage, it's a pretty good bet that that engine is pretty much used up. The compression test should expose that. I would also expect that those 2 cylinders share the same DIS coil circuit which may be very weak. The the oil starts fouling the plug, the weak coil won't be able to overcome it as easily so a new coil may buy you some time but won't resolve the underlying problem.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



MOBowhunter
New User

Dec 9, 2013, 1:56 PM

Post #6 of 8 (1746 views)
Re: Misfire at cold and certain MPH Sign In

grr

over lunch I pulled the plugs and replaced them. Cylinders 1 and 4.
They were baked badly. One all black the other all white just huge amounts of buildup I don't even understand how they fired at all. Didn't have time to check 2 and 3.

I did notice that threads on the plugs were wet with oil, not charred but wet.

Is this indicative of one thing or another? Wasn't expecting to see wet oil and on the threads of all places.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Dec 9, 2013, 2:06 PM

Post #7 of 8 (1741 views)
Re: Misfire at cold and certain MPH Sign In

The wet oil on the threads is just a leaking valve cover at the tube seals. That's no big deal but the caking on the plugs is oil being burned in the cylinder. I'm afraid you got your money's worth on this one. It's time to retire it.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Dec 9, 2013, 2:23 PM

Post #8 of 8 (1738 views)
Re: Misfire at cold and certain MPH Sign In

Toss those plugs and hope to buy time to find another car. Pretty good guess and I think HT concurs that this engine has had enough and not cost effective IMO to fix.

You didn't ask but if you expect 200K at all it's a crap shoot if you take wild care of things all along. So that money you saved put toward the next,

T







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