Help 99 Camry Misfire Mystery

[bbs360]

130,000 miles My 99 Camry has a terrible misfire. The problem is not as noticible at idle but anytime the car is under a load it is very noticible. I am getting p0300 - p0306 codes. It is completely random. I can clear them and different codes will appear but they are always the cylinder misfire codes. It has stumped two independent shops and a dealership. None of which tried very hard to figure it out in my opinion. I have replaced all plugs with OEM spark plugs, Wires, Coils, fuel filter, fuel pump, TPS, MAF, and swapped around fuel injectors with no real leads. I saw an improvement with the fuel filter, MAF, and spark plugs but they probably were just worn anyways. I am thinking next to try the crankshaft position sensor but my concern is that I am not getting that code. Other sugestions I have received are Camshaft sensor, EGR Valve, PCM malfuntioning. Any help would be greatly appreciated especially with money running in short supply.

[ECale3]

a bad oxygen sensor can throw things off too (and kill gas mileage).

[DressUpYourPet]

I've been where your at, mystery engine misfire. And you can go through a bucket of money trying to fix this sh%t too as you well know.
I have only a couple suggestion that might be useful to you as you sound like you already know your way around an engine:
-disconnect EGR hoses and plug them and drive it around for a little. If this makes a difference in the engine performance, better or worse, EGR is probably functioning. If it makes NO difference, maybe it is EGR after all.

-Back to basics - do a compression check. Testers are cheap at
http://search.harborfreight.com/cpis...ster&Submit=Go. The online manuals here will tell you what the psi reading should be. If low in one or more cylinders, thats one of the problems if not the only one

-Could be a sticky valve or a valve thats worn to too tight a valve clearance. (Your shop probably never even thought to test for this problem.) I had this problem once with my old Nissan 200sx, except it only happened at startup - some valves were too tight and some were sticking. I'd try dumping Seafoam or Marvel Mystery in the oil and/or do two oil changes in a row, use 5-30 and see if this makes a difference. If it does, maybe a valve was stuck.
Another old timer's trick you can do - caution - is just briefly floor it while driving on the freeway - for about 10 or 20 seconds and back off the pedal. Do this a couple times (dont need no stinkin tickets) if they were stuck this may make them unstuck. Probably shouldnt need to do this more than once or twice though.

-if there are parts and sensors you think might be the problem, rather then run down and pay $$$ for the new one - go to your local pick a part junkyard first and pick the parts up there. Because you dont want to be paying $200 for a new sensor or something, and the problem is still there afterwards and find out they wont let you return it or something!

[bbs360]

Thanks for the tips I'll have to test them this week.

[bbs360]

Thanks for the tips. I've tried everything now. I tested compression and they were all consistent. Crankshaft position sensor, camshaft position sensor, EGR valve all checked out ok. I'm still at a loss.

[bigdaddymak20]

Sounds like a fuel pressure problem. Its says you replaced the fuel pump but what about the fuel pressure regulator. It is what gives you max fuel pressure when you push down on the gas. I agree good tech are hard to come by but who can blame some cause no one wants to pay the labor to fix this condition. Should have took all the money on parts and payed a master tech the three or four hours labor it would take to track down something like this. I would check and see if anyone has done a fuel pressure test cause a new fuel pump with a bad regulator wouldn't fix anything.

[bunkergod67]

i have cylinders 2 and 5 misfiring on a 99 camry new plugs,wires, fuel filter. Checked egr,coil packs, injectors. Feels like im never going to find the problem. Let me know if ya have any tips thanks john

[96CamrySport]

I agree with bigdaddy - sounds like a fuel problem. If you've had misfires on all cylinders, then it's a large fuel control problem, such as fuel pressure or metering. I think it's time to take it to a quality shop, tell them everything that you have done yourself, and have them find the problem. Your fuel trims and o2 outputs should show the way. Other options are that you have fuel contamination or that your injectors are way too dirty. My hunch, and where I'd start if it was mine, is that an injector service/flush should be performed, such as a Motorvac service or a BG 3 part cleaning service. Oh, and attach a gauge to verify fuel pump pressure output FIRST.

Next, have you had any other codes show up? you may be ignoring a hint. Any other information? When it happens? I assume the rest of your tuneup is up to date, too? does it happen cold or hot, or both? highway or city driving? when you floor it, or light throttle?

[bigdaddymak20]

make sure the plugs are ngks or denso plugs with the double ground electrode. after market ignition parts dont work well with toyotas.

[cmjohnson]

You're missing something very important: The ECM itself.


Early this year I had an issue with intermittent roughness in my '92 V6 LE. When it ran rough,
it was dumping raw gas out the tailpipe.

The problem got worse, rapidly. And after extensive diagnostics, it turned out to be nothing but a bad ECM.


200 bucks for a guaranteed replacement from a junkyard later, problem solved.

The ECM is the only thing I can think of that could cause your problems given the diagnostics and checks
you have performed up to this point.


CJ

[bbs360]

Thanks for all the tips. It was the coils. One went bad and by the time I replaced the one, the increased load on the other two had made them go bad also. Remedy; replace all three coil packs at once. She's good for another 200 K.

[romeo511]

I have a 99 Camry and I was told I needed a new engine cause of a misfire on cylinder 5. I don't believe I need a new engine. So does anyone else know of any solutions to fix this. I've had a tune-up and everything done to it. Any advice would be helpful. Thanks.

[Mike Gerber]

Originally Posted by romeo511

I have a 99 Camry and I was told I needed a new engine cause of a misfire on cylinder 5. I don't believe I need a new engine. So does anyone else know of any solutions to fix this. I've had a tune-up and everything done to it. Any advice would be helpful. Thanks.

You need to be more specific about what code(s) you are getting and what was done to the car. A tune-up means lot's of different things to different people. Also, how many miles are on this car/engine?

Mike

[73sport]

Originally Posted by bbs360

Thanks for all the tips. It was the coils. One went bad and by the time I replaced the one, the increased load on the other two had made them go bad also. Remedy; replace all three coil packs at once. She's good for another 200 K.

Glad you posted the FULL circle concluding your fix!

Everything points to ignition faults and I was about to suggest your NEW parts were bad.

Peoples; never discount the fact that NEW parts can be defective. Yes, We'd all like to give them the benefit of doubt, but when it comes to ignition, they can have defects. It sucks and I've been there, but you just have to be persistent.

Think in terms of risk, what part is under the highest demand to deliver?
- fuel filter = low probability of replacement failure
- fuel injectors = not likely to be random
- fuel pump = not likely to be random
- spark plugs, new is unlikely but possible
- BUT Ignition/ignition wires and coils subject to 40,000plus volts can be random and can fail even if new!

There are MANY 199#'s and even 20## cars with bad coils coil packs. It seems Toyo has an issues with high voltage break down over time.

Glad the coils fixed this one!

[df0318]

What about the cold engine? How it causes misfiring? Seems I get it on my 96 1mz-fe. When the engine is cold, the car starts normal, but jerks during the first mile even when you slow down. And somehow it rans smooth after a full stop without shutting down. It has not hit 200,000 km yet.

I have replaced plugs, wires.