Need a little repair advice

Hey guys,

I've had great success finding solutions to my VFR / Kawasaki tech issues on this board. I was hoping someone may be able to shed some light on my car issues as well. Here's the issue:

I've been trying to diagnose and repair a Check Engine code P0300 (random misfire) on my 2003 GT manual transmission with 85k miles without luck. Here's the situation:

I left my car parked at "some guy's" place to install a new clutch, and ended up having it stored there for 8 months until I returned from school. By stored I mean just parked outside, sitting there. The clutch was replaced and worked great. I drove my car which had been sitting with 8 month old gas in it, from Syracuse, NY to Burlington, VT. It ran like a loud, rough, piece of shit, until I refilled my tank about halfway on the journey to VT. I put fuel injector cleaner in it with a fresh tank, and it ran much better, but still rough. P0300 code was thrown by the time I got there.

The issue has been going on for over 2 years.

I have replaced the:
- air filter
- spark plugs
- spark plug wires
- distributor cap
- rotor button
- engine mounts
- full 60k service

Since these repairs, which were done over the last two years, the car's idiling, fuel efficiency, and power have increased dramatically. Instead of throwing the code before a full tank was burned like it used to, it now takes about 2,500 miles to throw the code. I can hear it, at least I can feel it, misfire at idle, but while cruising I cannot detect it through hearing/feel.

I'm not positive, but I feel as though it misfires more often when it is very cold out at idle, and less when it is warm out or warmed up at idle.

I suspected that the fuel filter is clogged from sitting with bad gas, and that the pump is not running strong enough at idle to get the proper amount of fuel delivered. The dealership told me that wasn't possible, and that for $1,700 they would do a more in depth diagnosis with no guarantee. They're lying bastards. I also paid this dealership $75 to inspect my engine mounts, which they said were tip top. In reality, all 3 + tranny mount were completely ripped through, and my engine lurched forward when gassed.

The Car:






Anyone have any suggestions?

Update:
- Cleaned throttle body
- Checked compression
- Fuel Injectors Pass a Resistance Check
- Cleaned the Idle Air Control (still dirty, but best I could)
- Cleaned Mass Air Flow Sensor
- Replaced Battery

Here is a look at the Tachometer when the car's warmed up at idle: YouTube - 2003 Eclipse GT Tachometer Gauge (Hunting Idle) P0300 Random Misfire

A look at the idle with the MAF unplugged: YouTube - 2003 Eclipse GT Tachometer Gauge (Hunting Idle) P0300 w/ MAF UNPLUGGED

A look at idle with the Catalytic Converter bypassed: YouTube - 2003 Eclipse GT Tachometer Gauge (Hunting Idle) P0300 w/ CAT UNHOOKED

Here is a look at the plugs:

The plugs:





The oil wiped off the threads:


The wells:

 

check you r sensor wires that are located anywhere near the transmission that might have been removed stretched reconnected during the time you had the transmission fixed.....you should be able to check the fuel pressure with a gauge right on the injector fuel rail....... you should change the fuel filter anyway after sitting for 8 months I would ...

 

A bad MAP sensor, Mass flow air sensor, or TPS (throttle position sensor) could all cause an intermittent code and/or missfire such as you describe. But, the code for any of the mentioned sensors should have popped up as well... Sorry, I guess I got nothing.:redface:

 

Thanks for the reply. I tried checking the fuel pressure today, but unless I want to cut the fuel line in half I need to by a mitsubishi special tool to do the fuel pressure check. It's really just a fancy adapter that a gauge can be connected to, but is not possible to check it without.

I was told that the fuel filter is located inside the gas tank, and is not serviceable (said the dealer). Which is either a terrible design, or I'm being lied to.

 

Hey, thanks for the reply JTC. All this time I've been begging for another code to creep up but it hasn't. Another code like a sensor code would give me a better handle on where to go with this. But since there are no other codes, all sensors and should* be working properly.

 

If you have a multi-meter you can check the voltage on the TPS. I don't know what the spec is for your car. But, on late model Chevy's with LT1 engines its supposed to be .5 volt, and it won't throw a code until its off by more than .1 (.4-.6). By the time it displays a code the engine smoothness problems are readily apparent through sound and feel as you described.:crazy:

 

A bad (faulty or dirty) MAF sensor will throw the P0300 code. Unplug the MAF and see if that eliminates the problem. If it does, try cleaning it with contact cleaner.

 

Could be a bad plug wire. Could be a flaky engine light. If I am reading it right you car is running OK. Try dumping the computer and for sure dump the dealer..or at least get them to spring for a large tube of KY..

 

I just took another video of the Tachometer with the MAF unplugged. It looks like I'm getting a similar wandering idle, but it is not as bad. I'm not sure if that's because the engine is idling at a higher RPM or what.

Video: YouTube - 2003 Eclipse GT Tachometer Gauge (Hunting Idle) P0300 w/ MAF UNPLUGGED

 

Well, I'll throw in my 2 cents. (as background I am an ASE master certified tech that graduates college in may.) The most likely cause of the running problems after sitting for 8 months would certainly be fuel system related. I can tell you right now its not the fuel pump or the filter. If that were the case, the engine would run worse under load as the pump would fail to provide enough fuel to feed the demand of the engine under load. It seems from your description it misses mostly only at idle. I would be willing to bet that one or many of the injectors are partially clogged. To be sure, make sure that the mass air flow sensor is clean, they make a spray cleaner for that. Where the manifold absolute pressure sensor bad (if it has one, few MAF systems run MAP sensors as well) it would likely throw a code for it. As a last resort, before thinking about replacing the injectors I have a plan. At the autoparts store where they have the fuel system cleaners find the stuff in a metal can that is called SeaFoam. Get yourself a bottle of that. Now, run the car down to close to 1/4 tank, then pour the SeaFoam in the tank. Now... heres the fun part. Take the car out, and beat the living piss out of it. You want lots of fuel, and consequently lots of cleaner flowing through the injectors. Drive it til it needs gas, fill her up and see what happens. Keep us posted.

 

I had a Chrysler product with the same problem back in 08 and after going over it with a fine tooth comb I went back to the basics. After a compression/ leakdown test it turned oot that it had slightly bent the exhaust valves and that was the cause of the misfire. It was a family friend and can only guess she missed a shift and mechanically over revved the engine and tipped the valves. Aside from the check engine light and the not quite perfect idle it started and ran very well A compression/leakdown check may be in order just to be sure.

 

My wife's Honda Pilot was throwing error codes for cylinder misfire and it somehow turned out to be related to a bad battery.

Rollin

 

I thought that may be an issue, but the dealership said that I was crazy. My battery is 5 years old, and isn't bad but still "good" says advance auto parts. I've been thinking about replacing it but wan't to do a little more diagnosis before throwing more parts at it.

 

I think this has become a more common practice - putting the fuel filter in the gas tank. I don't like the set up personally, but I don't think they're lying to you (on this particular comment).

 

I would have never guessed it was my battery but when I replaced it the problem went away and never returned. If your battery is 5+ years old anyways I don't think it would be a complete waste to replace it anyways. Maybe you can find someone who can loan you their battery for testing purpose?

Rollin

 

Just for grins, connect a multimeter to the battery and see what kind of reading you get, should be a steady 14 volts give or take just a bit.

 

I personally like the SeaFoam idea. After sitting for 8 months, the gas should have been drained and new fuel in it's place prior to even firing the poor thing up. Sucking all that nasty fermented fuel in through the injectors, throttle body, and the deposits that are left behind in the cylinder from burning dirty fuel can do horrible things to an engine. A full bottle of SeaFoam along with a full tank (15 gal min) of high test at hard acceleration for as much as possible (OD off helps) will clean out the injectors and most of the throttle body as well as dissolving the piston heads and combustion chamber near the valves. If anything, it won't hurt it by cleaning it and at $10/can its a cheaper fix attempt than the battery.

IF this doesn't fix the code issue, then I would replace the battery. The last time I had a battery that actually lasted 5 years I was living in Delaware. That was 12 years ago. Here in Arizona, the desert heat kills a premium 7 yr battery in 2 years flat. Even the OEM batteries only last about 3 years at the most. Batteries are tricky creatures. They can show a full charge of 12.2 VDC and look fine on a multi-meter, but when you put them on a load tester then can drop down to 8 VDC in a hurry. If the battery is weak, even though the charging system is running fine, it will not be able to run all the electrical components that are in modern day sports cars like yours. An alternator can only hold the charge on the battery to the point of where it was prior to the start of the engine. It's a myth that running a car for a few hours will charge a battery back to full again. When a battery dies or gets low enough to the point it won't turn over an engine, and you jump start it, the alternator will only fix it by about 25% of it's original charge. At idle, the alternator is only putting out the minimum required to keep the engine running and is not in fact charging the battery. The only way to recharge a battery is with a deep charger or a trickly charger. Once a battery has lost its thickness in the plates though, it will never hold more than 80% of it's charge again and must be replaced.

Basically, all that boils down to this. At idle, it's the battery voltage that is running all the electrical components. Put your battery on a load tester. If it falls below 10.5 VDC then it needs to be fully charged. If after charging it still drops, then it needs replacement.

Hopefully this helps?

 

I think that's some solid advice. I put off the shelf injector cleaner in it a few times, but obviously without luck. I haven't thought about putting SeaFoam in it though. I believe I have a 14 gallon tank, should I do the more aggressive approach of 16oz SeaFoam to 3.5 gallons of gas? I think thats 4.5 times the recommended "dosage". Then again, the recommended dosage with other products has not produced a result.

Also, I cleaned the IAC and MAF today, and both seem to be working properly and are clean.

 

I've never missed a shift and a compression test showed that the engine had good compression, and was pretty equal across all 6 cylinders. Good suggestions though, that was one of the first things I checked.

 

Now I'm looking for a good way to test whether the catalytic converter is plugged up from sitting there, or from trying to burn off all that bad gas in the first place. It may be worth noting that while the car isn't slow, I used to be able to smoke the tires just from slamming on the gas in first, but now is no longer possible without dropping the clutch.