tollster

I am away working and during my commute to work,my gas engine in my 02 toyota tacoma develped a serious miss. It is a distributorless 6 cylinder with 100k.
The check engine light started to blink intermittently, and then stayed on continuously. The weather has been in the 40s-50' with the exception of last night when it got into the mid 20's. I did notice upon starting it this morn that is seemed to run a little rough, but no miss. The miss devolved after about 10 miles and was warmed up at that time. The engine does not stall, but seems to be running on 4 or 5 cylinders, no power; it also seems to surge at low RPM with steady throttle.

I had my O2 sensors replaced last fall as the check engine light was on then, but no signs of trouble such as missing etc.

There are also no signs of a blown head gasket, no rotten egg smell, no moisture from exhaust, or bubbling up through the radiator.

The gas gauge is at 3/4 full, I arrived here Sunday after using 1/2 tank from my local town gas station where I have always purchased fuel, I topped off here on Monday morning which would be 1/2tank, I added another 1/4 tank from a different local station on Tuesday.

I did not experience any issues until today and everything seems tight under the hood, no loose fittings nor vacuum lines, no loose plug leads nor are they crossed as the separators are in good shape.

I added 3 cans of gas HEAT to my tank leaving work, drove 24 miles with no improvement as i believe it may be water in the gas, but now I am not sure.

I am wondering if I burnt an exhaust valve now, its ruff at idle but seems fine at 2k RPM, I also held a piece of paper over the exhaust and it seems as if there is some intermittent suction, but its hard to tell. Under hard acceleration off idle it will backfire through the intake.

Any suggestions?

justin_4runner

u need to pull ur plugs and look at them.. also is the computer throwing a code for a miss fire in a cylinders? it sounds like u could have a coil pack that is going bad,

tollster

Yes, misfire on cyl 3&4: multicodes: mav sensor, ignition issue , rich lean fuel mix, large vacuum leak, fuel injector plugged or blocked:
Numbers a300, a303, a304

is it possible to loose 2 pacs at once? I traced the plug lead from cylinder 4 and it goes the the coil pack on cylinder 1. Was really hoping it was gonna go to 3, which bring up my question?
Each coil pac controls 2 cylinders, is itpossible to loose just 1/2 of the coil pac or one cylinder?

from what I was told from the parts guy at AutoZone the firing order from front to back of the drivers side is 2, 4, 6, passenger side is 1, 3, 5. so if thats the case my twon inner most are misfireing.

Also is it possible to have some spark when these fail, or do they have no spark at all? Sometime my truck feels fine, such as a high idle, or no load. Butas soon as I throttle up to make a hill or pull out, it stumbles and continues to stuble until i let up. They engine light never goes out.

Sorry such long winded, I limped it home 160 miles today, and really needmy truck monday for work, starting 6 days a week 12 hours a dayfor a month,so this is my last chance to get it right.

Thank you all,and happy I found you,
-Tol

justin_4runner

i wouldnt think u would loose 2 packs at once but u never know... so what things have u looked at or done so far? it sounds like a couple things happening, have u changed fuel filter, spark plugs or air filter? do u have a fsm i would also check the throttle positioning sensor or the afm

Kiroshu

Whens the last time you put a good set of wires and or plugs on it?

p0300 p0303 p0304 <-- those are the only codes that were show correct?

If thats the case start with plugs and wires "clear the codes" and go from there.

tollster

Yes those where the only codes that showed up.
I replaced the plugs, pacs and leads about 40-50k ago, however they where not from the yo dealer.Have not worked on truck yet as I was away from home working, limped home today and will wrench tomorrow.
I will start with the pacs like you said Kiroshu and take it from there,also will get fuel filter like justin said and run a can of BG44K though it for the injectors and any carbon deposits.

tollster

FIXED

Replaced coil pacs (3) plugs, and leads. Light is out, no stuble or miss, very smooth idle.

I was mistaken when I said I replaced the pacs before as they looked to be the original Nippsadino, so It was only plugs and leads I had done previously.

Anyway, thank you for all you help here.
-TOL