Engine Enigma
 

Symptoms : rough idle, missing, loss of power.
Codes : Miss fire on Cylinder 2
Mileage: 171,680

So 15 min into my daily drive last friday, all of a sudden it starts missing and acting like it is choking itself at 70mph. Check engine light comes on steady, then turns to blinking. Immediatley stop and get it to a shop. Get it on a scanner this is the only code I have recieved, " misfire cylinder 2". So here is what I have done.

1. Replaced plugs and wires: still get miss fire code
2. Replace all 3 coil packs: still get miss fire code
3. Compession test: All at 175-183 - still get miss fire code
4. Check Catylitic : Clean and clear: still get miss fire code
5. Checked oil for leak and crossing of different fluids - none seen.

After each step above the engine runs perfect for 10 -15 min then once warmed up same choking issue happens.

I have searched God's green earth and have found NO EGR valve and the dealership says there isnt one so I believe them. Anybody know otherwise?

Any help?

What vehicle is it?

97 4runner V6. Engine is th 5VZ-FE

sounds electrical in nature to me. Have you gone through all of the sensors(temp, oil pressure, AFM) my truck has a carb so I don't know what else there is). You can clean the mass air flow meter I believe, and clean out the throttle body? Just tossin' it out there but sound electrical for sure so I think you may be on the right track

I knew someone with a 02 Taco that had this and he did all the same stuff (coil packs, wires, plugs, ETC).

Finally I suggested to him the only thing left that it could be is either the crank or camshaft position sensor is bad.

Sure enough he changed out the crank sensor and it runs like a top.

This is a common issue on allot of vehicles that drives even experienced mechanics to pulling out their hair. It will test fine if you ohm it out when its cold because it only acts up when its hot.

i had very same problem in my 99 4runner...tried everything...ended up replacing # 2 injector...runs like a champ now....if you will be doing it yourself its a good time to upgrade all injectors....hope this saves you some time.

wouldnt a bad injector act up all the time? Why would it wait until it was warmed up?

mine did exact same thing...when warm would run rough like you described..i got a stethescope and listened to the injectors...the #2 injector had a much diffrent sound...i did everything that you have so far and more...you can buy a stethascope at autozone for 8.99...its a pain in the you know what to get to that #2 injector to replace...pm me if you want ive got time to help you out.

Possible injector. 3.4s have alot of injector replacements over time. If I ahd to make a guess i think injector. Is there any other codes besides miss fire #2? If not then injector. Possible Air flow issue.

A bad injector could do it. If you're pulling them out, send them to witchhunter performance. They benchtest and clean the injectors and give you the data for $19 per injector and a flat $10 return shipping. VERY fast turn around with those guys. Most places want $200 ~ $250 to clean a set of 4 injectors.

On a different note, I had similar symptoms on my 89 5.0L chevy. Turned out to be a blown HG. Might be worth checking on.

just found these on ebay..would get you by for awhile if your on a budget..i ended up buying one used at a junk yard for 50 bucks..http://cgi.ebay.com/ebaymotors/TOYOT...s#ht_500wt_976

he checked compression...was ok...would be lower if blown hg..

i have this same problem. misfire on #3.. i replaced the coil. nothing. i think i'll try maf next before injector

Conclusion - Injector. Figured others would like the follow up.