Rough idle and missing

I have a 2002 v6 4door Prerunner TRD
Yesterday my wife started up the truck to come home and it started rough and has no power. Seems like the truck is misfiring. Sounds like a little rice burner. Local shop checked out the wires, plugs, and module units at each cylinder. When at idle the truck was throwing misfire codes all over the place.

Left the shop with no answers wires good, coils good, plugs good. They said it might be the computer. Any ideas?

I am thinking injectors or computer???

 

Not sure, I need to get a reader at home. When he had the more expensive diagnostic computer hooked up it did not show a misfire while driving even though obviously no power and sounded like a honda civic. While at idle the cylinders were randomly misfirng like crazy and real pretty rough. The engines settles into a type of surge if left idling.

 

You didn't put in aftermarket plugs did you? Or aftermarket wires? If we had the codes, it would really help. Were they P0300 or similar?

P0171? I've seen air flow meters do the same thing, and also set cat codes at the same time (P0420), and lean conditions at one or both of the O2 sensors.

 

Will get codes. I changed out the plugs before a trip in April from Florida to Illinois. Not a single problem until yesterday. Do not remember what plugs were put in (think NGK). Will pull one in the morning.

 

A lot of Toyotas won't tolerate aftermarket plugs. They usually just set codes, and not all the roughness of idling your describing. I'm betting it's something else.

 

The plugs in the truck are Bosch Platinum 2s. Anyone know where to get an electronic version of the shop manual? I have the Land Rover Rave program for my old discovery and the thing is great. Can't find one for the Tacoma. The Hanes and Chilton books never seem to help enough.
The codes the truck was giving this morning are:
P1300
P0306
P0305
P0300

 

I would take a look at fuel pressure too, along with the plugs. I believe these still used the waste spark system, making spark plug type and gap critical. Also, make sure the coil pack for cyl. 5 and 6 is screwed down tight.

 

If you get factory plugs, they'll be gapped for you. If you drop one, it's toast, go buy another one.

Your codes are cylinder 5 misfire, cylinder 6 misfire, and a random misfire code (P0300). The P1300 is an igniter circuit malfunction. Check your coils for the spark jumping outside the boot, and hitting the side of the spark plug tube.

Get rid of those Bosch plugs, and you should be back in business.

 

I never worry about it. If they're not right, I get paid to do 'em again. Sometimes it's nice being paid to work on cars!

 

Thanks for all the help. Let you know how it turns out.

 

if its an 02, get the ngk platinums. thats what pepboys recommended and my 4runner runs great. good luck

 

He's already got aftermarket plugs, and that's what's causing his problems. Why would he put in another plug, that's most likely gonna cause the same problems?

I'm a Toyota certified mechanic, and I do not recommend Bosch, or NGK plugs. I think I'm more qualified to diagnose an engine miss, than a kid at Pep Boys.

 

Check to make sure all the plug wires are securely "snapped" onto the plugs. I changed out the plugs on one of my other cars and neglected to "snap" one of the wires properly onto one of the plugs and it ran like crap and was missing. Snapped it back in and it runs like a charm.

 

Wires good. Can't get the plugs until Monday. Everyone is either closed or has to order. We had no reports of misfires when driving the truck, even though it only had half the power and sounded like crap, with the real time diagnostic computer attached. Only when we came to an idle did the misfires start to report and throw codes. Anything else that is a likely cause I could try today? Seems like the plugs may be throwing the codes but not the overall problem. Everything is hooked up good and no visible arching when it was completely dark out.

I just do not want to screw something up worse trying to find the problem. By the way how are the cylinders numbered in the six cylinder?

 

Don't over-analyze the problem. Start with the plugs, and go from there. I'm sure that's your problem.

The cylinders are numbered in this order. Looking at the truck from the front, cylinder 1 is on your left, in the front. Then 3 and 5 on that bank. The opposite bank is 2 4 6, starting from the front.