Random missfire

[therock]

i got my car up to autozone and the random missfire code came up what can i doim going to change myspark plug wires tomm but could i possibally be the coil pack

[Clark Griswold]

Hard to diagnose that without logging while it happens. I also had the 0300 random missfire code, but was clueless until I found out it was cylinder 5 and 2. So for me it's either that one 5/2 coil or 2 wires. If it's ignition related.

[therock]

well i had my friend that works at a toyota dealership come down and run it on hsi scanner and it said the same thing but didnt give a cylinder now yousaid its hard to tell with out logging whats does that mean

[terminaldegree]

In order for my mechanic to diagnose it for sure, I had to drive the car for something like 5 miles at 55-60mph while the car was hooked to the computer. Until we did that, all we got was a "misfire detected" code. Afterward, I was able to isolate a misfire count and the obvious culprit was cylinder #3.

The coil can be tested to some extent with a multimeter. You could just buy one coil pack and swap it around until it goes away. I replaced the wires first, as you're thinking.

[Blue Flame V6]

Could be a fuel pump issue or fuel line. Got that code when my friends 96 fuel line got pinched.

[Clark Griswold]

Originally posted by therock:
well i had my friend that works at a toyota dealership come down and run it on hsi scanner and it said the same thing but didnt give a cylinder now yousaid its hard to tell with out logging whats does that mean

You need a scanner hooked up to the car when the missfires happen. The code itself won't tell you which cylinder it is, but with a scanner you can look at each individual cylinder and see what happens as it happens. I am using www.hptuners.com which has a build in scanner. You can buy a standalone scanner for half the price like an AutoTap. It depends on your needs. HPTuners can also edit your pcm, which is a very powerfull tool.

If you're on the budget, just get new plugs and wires for now. If you see the SES flashing again, then maybe it's the coils. If that doesn't solve the issue then might be fuel related.

Another great thing about the scanner is that if you see a missfire at a certain cylinder, then you switch the coils around and the missfire moves to a different cylinder, you know it's the coils. Also you can change just that plug or check just that wire that is hooked up to the bad cylinder. Might even be a clogged fuel injector. I just got new plugs/wires/coils/module and I have a walbro thats only 2 years old. So my problem could be a fuel injector.

[therock]

so if i go to autozone they will have to drive my car for a little bit and than the missfire will show up

[terminaldegree]

I don't think autozone is going to go and drive your car for a little while. At least, not for free.

I'm not usually an advocate of throwing parts at problems, but the cost of OEM plug wires and an OEM-style coil to try switching around is less than an hour's labor in most areas. Heck, all that plus a set of AC plugs is cheaper than some shops I've seen around Austin... All of these things are pretty easily reachable on my car. But my exhaust manifolds are different than yours, so who knows.

Otherwise, hire a mechanic for a half-hour to sit in the car and monitor it while you drive. I don't think you can get out of this for free.

[therock]

well ive replaced the wires and plugs and still no diffrence so im saving the injectors and coils for tomm but how can i tell if there is a prob with the injectors

[James5036]

This happened to my car...cylinders 4 and 6 were the alleged misfires...the mechanic changed out coil packs etc...but there was still a misfire, so he ended up going through each cylinder and reseating them...if that's what you call it... and naturally did a tune up after having taken it apart.

No more problems. If you can do it yourself, great, but if not, try and find an independently owned garage run by a family and chances are you'll get a good deal. The cost for my job was $300.

Dealership would have screwed me over big time.

[therock]

hey i live in dallas to weres the shop you went to man im really instrested that sounds liek a great price

[Clark Griswold]

This is really weird cause after I moved my coils around to see if my missfire moves, it went away totally. I think maybe my coils were not seated right.

[therock]

well it turns outmy igniton module was bad failed all 6 test so im going to get one today and hoping that solves all the problems becuase school starts tomm and my *** aint walking

[Speed Freak]

The random missfire code came up on my car when my cat was cloged. At first it would just flash the ses light then it finaly threw the random missfire code .
The car never threw a code for a bad cat.

[Clark Griswold]

Originally posted by Speed Freak:
The random missfire code came up on my car when my cat was cloged. At first it would just flash the ses light then it finaly threw the random missfire code .
The car never threw a code for a bad cat.

Thats because the flashing SES light is a cat killer. Really hot unburned fuel will melt a cat fast.