No similar thread: 2003 with PO300, rough start VSC OFF/VSCT lights

[BillB]

In my continuing saga to get the 2003 4runner, I bought used, working right, I have gotten past some problems and continue with starting problems.

When the vehicle is started it sometimes just starts right up and sometimes it runs rough until I run it up to about 2000 RPM and let it go back to idle. When it starts rough, sometimes I get a Check Engine Light (CEL) and the VSC OFF/VSC Track lights. When I look at it with the OBDII scanner I have a PO300, Random Misfire, code. When I have taken the vehicle on trips after driving for 60 to 80 miles, there tend to be problems every time we stop.

My wife drove it the other day and it "hiccuped". The scanner reported a PO304 code but she said she didn't feel any roughness but the lights just came on.

Any ideas?

 

[paperchasin]

I'm not sure how useful this is, but I didn't see you mention this. You initially had P0300 code for random misfire....and now more recently P0304 code, which indicates misfire in Cylinder 4. I would start by checking that spark plug, as it is the simplest thing to do.

 

[bamma]

Could be a variety of things ,but most likely the spark plug/coil and wires. Check them first. When were the plugs last changed? Could also be a clogged or faulty fuel injector.

if not the plugs ir injector, it could be signs of a bad cylinder.

 

[BillB]

Bamma,

I changed the plugs a couple of weeks ago. While I am not certain, the connector to the No. 4 may have not been seated properly as I was able to push it in a little and it felt like the "lock" clicked.

For all, this 4runner has about 128,500 miles on it. I forgot this in the original post.

 

[paperchasin]

Bamma,

I changed the plugs a couple of weeks ago. While I am not certain, the connector to the No. 4 may have not been seated properly as I was able to push it in a little and it felt like the "lock" clicked.

For all, this 4runner has about 128,500 miles on it. I forgot this in the original post.

Please keep us posted on what happens...

 

[BillB]

My wife and I took it on a 3 day 600 mile trip to the Texas Hill Country. It kept acting up with rough starts after it sat a while. I finally gave in and took it to a local independent auto repair shop. Their diagnosis is that the head gasket on the left side is leaking as has been reported many other times. Due to a valve timing problem repairing a similar Toyota engine in the last few years that caused them to have to replace the engine core, the shop declined to repair it. After thinking about doing it myself, I called the local Toyota dealer. Their estimate was reasonable enough that I am taking it there to get the head gaskets replaced.

 

[iBison]

My wife and I took it on a 3 day 600 mile trip to the Texas Hill Country. It kept acting up with rough starts after it sat a while. I finally gave in and took it to a local independent auto repair shop. Their diagnosis is that the head gasket on the left side is leaking as has been reported many other times. Due to a valve timing problem repairing a similar Toyota engine in the last few years that caused them to have to replace the engine core, the shop declined to repair it. After thinking about doing it myself, I called the local Toyota dealer. Their estimate was reasonable enough that I am taking it there to get the head gaskets replaced.

Add your name here.

Amazing you got a reasonable quote at a dealer.

 

[alia176]

I'm having similar issues!

Folks,

My girlfriend is having similar issues as well. Let me do my best trying to explain the symptoms:

- plugged in OBD scanner while driving and two codes are persistent: P0171, P0174.
- engine hesitates and stumbles like it's starving for fuel. Engine coughs, sputters, and accelerates poorly while stumbling.
- as the condition deteriorates, the engine fails to idle well and just dies.
- finally, the engine won't start or it won't stay running. At this time, codes are P171, 174, 300, 301, 302, 304, 306 & 308

Things done on the side of the road:
- unplugged POS batt term, reconnected. - improvement for a short while, just enough to pull off the road into a side road.

Vehicle seems to reset itself after sitting overnight like nothing ever happened. :mad2: This really pissed off my GF :mmph:

Ambient temp is pretty hot here in the SW, 95°-100°. GF took it to the dealership but they weren't able to recreate the issues. Things the dealership did:
- checked fuel pressure - ok
- fuel trim ok while driving
- wrote "can't condemn the fuel pump at this time, fuel pump maybe going out under very hot conditions and vehicle may need fuel pump"

My thinking:

- all of the 171,174 and 300 codes are the "effect" not the cause. When the ECU is trying to run the engine and it simply can't run at the proper air/fuel ratio, you're going to have wonky O2 numbers and cylinder misfires.

- some common denominators are: MAF sensor, fuel pump starvation, coolant temp sensors and I don't know what else!

- I'm ruling out spark plugs, fuel injectors and 02 sensors at this time.
-MAF sensor cleaned with spray cleaner

- I'm leaning towards coolant temp sensor unless there's another compelling item I should be targeting.

Thanks for your help.

 

[K_Labs]

Ok this is completely off topic sort of but my brother has a gmc Silverado 2003 or so with 200K+ miles. He had the same issue "random misfire" they told him it was a leaking intake manifold gasket. I know this is a completely different engine and manufacture. Basically I re-torqued per the FSM and it was fine after that. Just a thought.

 

[alia176]

Ok this is completely off topic sort of but my brother has a gmc Silverado 2003 or so with 200K+ miles. He had the same issue "random misfire" they told him it was a leaking intake manifold gasket. I know this is a completely different engine and manufacture. Basically I re-torqued per the FSM and it was fine after that. Just a thought.

I'd guess that an intake manifold would have the following symptoms that we're not experiencing: vac leak, hissing sound, constant hissing sound or loss of power, not intermittent issues that "fixes" itself after sitting overnight.

 

[alia176]

Mon update

I took my GF to her 2008 Runner on my way to work. We left it where it stalled, next to a VW dealership, LOL!! As she predicted, the rig started right up nothing ever happened. She jumped on the hwy w/o a single hiccup, hesitation or any of the crap that we encountered on the previous day. This morning the air temp was less than 70deg F.

Upon scanning the myriad of threads on this board about the DTC codes that i posted earlier, couple of recurring themes keep popping up:

- O2 sensors
- fuel pump delivery
- MAF sensor

I'll start a new thread if this one doesn't get enough traction. Feel like I'm hijacking the OP's thread.