View Full Version : Random Misfire Stumping Me 2UZ (100)

03-03-2011, 01:17 PM
Took it to Stapp Toyota. They said change spark plugs, clean MAF, clean Throttle Body. Said they checked fuel pressure, but when wife ask for the numbers, they said they couldn't give them to her.

Done all the above. It throws random misfires on all but 1 and 8, only threw a lean code once..( I think p171) Can't duplicate that code. Stumbles around 30-35 mph, more so when it's not under acceleration.

Need to fix in order to sell, no more need... Kids all driving.

Any ideas would be appreciated.

Enjoyed my first meeting last night. I am posting at the suggestion of a member, I'm not usually one to ask without giving first. So thanks in advance

03-03-2011, 01:29 PM
Injectors or ignition coil problem like Ricardo has experienced?


When you get it fixed, be sure to post up about the truck in the for sale section...Seems a lot of folks have been looking for a 100 series lately :thumb:

03-03-2011, 01:38 PM
I had one bad one awhile back and isolated it. This time they are all over but sporadic. I forgot to add that the plugs were wet, i think that also indicates running lean. The radiator hose came off when my son was driving, and it started acting like this shortly there after. And thanks for listing suggestion.

03-03-2011, 05:38 PM
The plugs were wet under the plug wires? Or they were went on the electrode side?

Sounds like something got wet when the radiator hose came off and is causing problems now - hopefully one the guys familiar with the 100 series will chime in here...

I wouldn't bother with the dealer anymore though if you can't figure it out...I'd PM Robbie (aka powderpig (http://www.risingsun4x4club.org/forum2/showthread.php?t=10843)) and pay him to fix it right for you :thumb: - As a bonus, you could have him check out the entire truck and maybe provide you with a pre-purchase inspection report for anyone interested in the truck. If the potential buyer is a RS or MUD member that report will be worth its weight in gold :D

03-03-2011, 05:51 PM
It doesn't sound consistent with the coil pack being bad. When the coil pack goes, the first symptoms are a stumble, hesitation when starting to move from a stop - feels like the transmission is going bad. Also, the OBD system has a P030x code, where x indicates the cylinder with an issue. The code is a Pending code until the CEL light turns on.

03-04-2011, 01:00 AM
Just for the helluvit, I swapped 2 coils , one from. Cyl 8 which never showed as a P308, and a coil from a misfiring cylinder(4) and the Code switched to a P308. So, I'll buy two coils see if I can clear up one side, if so, I'll switch all 4 side to side and see if the codes follow.

Thanks about pre-purchase inspection advice.

03-05-2011, 05:19 PM
Get the codes. Often there is more than one code thrown at a time. Just replacing coils, may not be the cause of the misfire. You can have codes read at most auto parts stores. Or buy a Scanguage for $150 and it'll tell you lots of information and can be moved from auto to auto.

03-07-2011, 10:17 PM
That's what I get for being too smart by half... It was two bad coils. They were next to each other( 2/4) so I guess it caused a P301 occasionally as well as the p302 and p304. And once a p305. That caused me to believe it was fuel/vacuum related. As I said before so did the dealership and they have slot more toys than I.
I learned from this to Keep it Simple. Just glad I didn't okay the $1800 fix:)

03-07-2011, 10:20 PM
Nice job figuring it out! :beer2: