OBD Code P0302, Sluggish Engine When Cold

[tonlun]

I have an '00 4Runner with 4 cylinder engine and 106K miles. Lately I have been getting a P0302 code. It is a misfire on #2 engine. I have been reading threads about changing the ignition coil pack to fix this. I swapped the ignition coils packs around and I am still getting a P0302 code. At slow speeds, when the AC is on and when the engine is cold, the truck is very sluggish. As soon as it warms up, it runs fine. I also noticed that the truck will most likely get a Check Engine Light when it is started and ran when cold. I would reset the light and as the engine continue to warm up and as long as it stays warm, the check engine light does not come on. It sounds like something is malfunctioning at cold temperatures. The only code that I am getting is P0302. Please help.
I have changed the spark plugs, checked the cylinder pressure (200 psi +/- 10), and replaced #4 fuel injector (different issue) but none seems to help. When pulled out the spark plugs, the plugs looked normal (ceramic center is dry and have a light brown color).

 

[toto]

The service manual mentions the Mass Air Flow (MAF) sensor as one of the possible causes for this code.
The MAF is a notorious source of strange problems, but sometimes you can just clean it rather than replace it. Search for "MAF" for more info.

 

[tonlun]

I bought a contact cleaner with mineral lubricant at Radio Shack and cleaned the MAF and #2 coil pack connectors. Snapped the connectors right back, started the engine cold and it is still behaving the same - sluggish. I took it for a spin with the AC on while the engine is still cold. It has no power even in the residential area. I did not get a new check engine light. But earlier in the day, my wife used the truck and the check engine light came on. The code is again P0302.

 

[toto]

I've got a 3.4L V6 (5VZ-FE) in a 2000 Tacoma. I would think this is still relevant for the 4-cylinder... I doubt the actual combustion process in the cylinder is that different.

Here's the list of possible problems in the service manual for P030x (x = the misfiring cylinder, 0 = multiple cylinders).
- Open or short engine wire
- Connector connection
- Vacuum hose connection
- Ignition system
- Injector
- Fuel pressure
- Mass Air Flow Meter (Sensor)
- Engine coolant temp sensor
- Compression pressure
- Valve clearance
- Valve timing
- ECU (computer)

You may want to check out the Toyota Techinfo Web site. For $10, you can access the service manual for your truck online for 24 hours. The manual is cut into lots of little PDF files, so you really can't download the whole thing. When you find the sections you want, you can save/print them. The URL is http://techinfo.toyota.com.

 

[bomer18]

P302

What I think your problem would be is:

It sound to me like two options sticking valve (intake) or have you check the resistance of the plug cable compare with the otherones.

Well if you want to try out I used for sticking valve on hight performance engine a formula 88(degreser)turn the car on minimun NEVER PUSH THE GAS spray some degreser in the intake hose do not diconet mass air flow meter do it after MAF sensor there is a hose about 3/8 after. Do it for a 4 or 5 time afetr that drive the car normally and see what happens.

don't forget to check the resistance of the cable if you don't know here itis: 25,000 ohms max per wire.

Good luck

Pete

 

[tonlun]

Boomer18: When you mention to check for plug cable resistance, I am not quite sure what you mean. I do not have iginition wires, I have coil packs on each cylinders and are mounted directly into the spark plugs.


Update: I have not checked out the Toyota Checkinfo but I will tonight.
It looks like that the sluggish problem is starting to show when the engine is warm and not just at cold. I can sense a slight sluggishness as I drive around the block with a warm engine.

I bought an extra fuel banjo bolt and I modified it. The modified banjo bolt connects to the inlet of the fuel filter and I attached a 3-foot long hose and a fuel pressure gauge to the modified bolt. The filter is only a foot away from the fuel rail and I have just changed the filter. I am assuming that the pressure at the fuel filter inlet is the same as fuel rail. The pressure read 44 psi at cold turn on. I even rev'ed up the engine and still, it read 44 psi. I drove around the block and monitored the pressure. It remained unchanged - 44 psi. I check the vacuum source of the fuel regulator, there was no vacuum even when I rev up the engine. The vacuum line connects to the inlet air resonator/connector. This resonator/connector is between the mass air flow sensor and the throttle. I am not quite sure if high vacuum can be created before the throttle. I induced a vacuum on the fuel regulator by literally sucking the vacuum hose. The pressure dropped by 10 psi. Then I thought, the resonator is bad. I checked for price at local dealership and it runs about $275 plus tax. On the other hand, K&N intake system costs $239. I went for the k&N intake system, installed it (the resonator is no longer needed), conneced the fuel regulator vacuum line to the vacuum tap on the K&N pipe. The problem was still there!! I checked the vacuum from the K&N pipe, there was none.

 

[greasefingers]

Hereis some more for you to read: http://www.obd-codes.com/trouble_codes/generic/p0302-cylinder-2-misfire-detected.php

 

[bomer18]

Misfire

You do have a coil pack but under the coil is a litlle piece of rubber connected to the coil it looks like 1 piece but in reality is 2. You have to check the rubber part make sure you don't have a crack sometimes you don't see it on nake eye.This is what I do pull the coil pack out get any spark plug and plug in the coil end,(do not used the one is IN leave thatone in)this only to see if you do have a good or weak spark, Use someone to crank the car try to put the spark plug pointing away from any soft part away from metal (hanging) remenber the coil pack needs a groung used a small caiman clips for that, you should be able to see the spark note how intence is the spark, NOW put a srew driver touching the rubbing part or coil end If you see the spark jumping you do have a faulty spark plug cable,What does it means when you car is warm or hot that piece of rubber it get softer, there is were loosing the spark.
I don't thing is a vacumm problem(reading what you already mention).

The code p302 is a missfire in the conbustion chamber, the only other problem,check node light and check for pulsation going in the coil remenber you do have a positive and you have a ground BUt ground is just a signal from the computer(pulsation),with the node light you can see both is easier if you do know how uesd a test light.

Also sticking exasust vlave(I mention by mistake intake before)check for that too.

If you nedd a electrical diagram for you car send me a email and I fax it to you.

good luck

 

[tonlun]

Boomer18:

I do not think it is the coil pack. I have removed all of the coil packs, attached spark plugs at each ends, cranked the engine, and they all sparked. I switched around the coil packs and still I was getting a P0302. Now, it is even worst, I am getting P0300. I still think the problem could be in the fuel system or timing (camshaft and crankshaft position sensors). I have been looking around the front of the engine but cannot find any connectors. I would think the camshaft position sensor is right around the timing chain area. I still need to resolve the vacuum source for the fuel regulator.

As for the sticking exhaust valves and check node light, I'll look into those. Thanks.

 

[bomer18]

No the coil pack

No buddy no the coil pack is the rubber part under you have to ground it with a screw driver.

Now if you are getting p300 is different check :

1)one of the major problem is(beleve or not coolant tempeture sensor knock sensor)
2)EGR
3)Mass air flow sensor

4) check for correct timing : ECM timing contrlled =3-19
:base timing =8-12


to check for base timing base : find a data link connector 1 in the left side of the engine compartmet it looks like a small black little box,with the engine on using a paperclip jump E1 and TE1 the timing has to be 8-12 and the RPM shuold be a 650-750.
Any question send me a email.

 

[tonlun]

Boomer18,

Can you tell me where the engine coolant temp sensor is and how do I check the engine timing?

 

[bomer18]

Sensor

The engine coolant tem sensor is right behind the upper radiator hose in the intake,( you can identified it shold have the colors brown/black and green yellow) We talk about everything but I have,nt ask you have you check the ignater? if you follow the brown/white cable going out of the coil #2, orange from #3, red from #1 they go to the ignater,When you find it (right side of the engine compartment)check the connector plug for corrotion or any typre of dirty,check for good positive(black/red wire) and good brown (ground wire).

To check timing you need a timing light(digital with RPM) cause you do not have scan tool(I guess)

Engine on and the trans neutral connect timing light and check timing it should be on 3-19. But the most important is the Base timing.
Engine on and trans neutral(on both a/c and all acc off) connect a clip (jumper paperclip)in the data link connector in the engine compartment litlle black box on the left side of the intake) jump E1 and TE1 and check for timing it should read 8 to 12 degres and 650 to 750 rpm.
I need to ask you how many miles can you get with a full gas tank.,
Thank you
Pete

 

[zduchene]

Page from my manual with diagrams. Hope I could help.

http://zackpix.com/p0032.pdf

 

[tonlun]

Update:

I checked each of the coil packs by attaching a spark plug one at a time. All of the sparks from all of the coils seemed to to be consistent in intensity and color. I also grounded a screw driver and touched it on the side of the rubber-end of the coil packs and did not see any arching across the rubber .

I also disconnected the EGR valve vacuum port and induced a vacuum. If I let go of the vacuum, I can hear the valve close.

I also attached an OBD II diagnostic tool which attaches to a laptop. I was able to read the O2 sensors output voltages, short term and long term fuel trims, throttle position, MAF air volume, coolant temperature, RPM, and timing advance. Everything seemed to be normal and responsive. The timing advance jumps quite a bit 10-18 degrees BTDC at hot idle. It reads more stable at higher RPM's (35 degrees at 2000RPM). When I jumped E1 to TE1 of the test connector, the timing advance read 5 degrees at 550 RPM and it is a lot more stable.

Thursday night, I was getting desperate, I opened up the head cover and checked the valve clearances. For the intake, the clearance is .006" to .010"; and the exhaust, clearance is .010" to .014". This is what I found interesting - one of the exhaust valves for #2 cylinder does not have a clearance. Cylinders #1 and #3 valve clearance were .001" and .003", respectively. All others checked out ok. Does anybody know what is wrong, could it be the tappets?