Not good.
Check engine light came on today, plugged in my reader and was surprised that 6 fresh codes were registered.

PO300 - Multiple cylinder misfires
PO301 misfire cyl 1
PO302 misfire cyl 2
PO303 misfire cyl 3
PO740 TCC circuit malfunction

Oddly, the truck doesn't seen to be running that bad, but codes like this could be a death warrant for a 14 year old truck.
Any ideas if theres a single thing that could have caused these sudden misfires ?

 

Anyone ?

Since this happened literally 1 minute after I got some gas, theres a chance the fuel injectors are fouled, so my plan of action, after checking for any obvious vacuum leaks, is to try some fuel injector cleaner.
Then new plugs/distributor/rotor.
If that don't work I'm screwed, but since multiple cylinders are suddenly misfiring, that would seem to point to either fuel or distributor, rather than something internal.

 

I got P0740 in Aug. cleared that code then it came back in Nov. From the researcher I've done, it's the TCC solenoid that needs to be changed. Haven't done it yet on mine, but I will soon. Odd enough, it doesn't feel bad. Also, you can get a misfire code if you have a clogged cat. You might wanna check that.

 

I'm cat-less, so I'm clear on that at least.
Right now I'm optimistic, I'm actually glad there are multiple misfires, if it was just one that would point to an internal problem on a specific cylinder.
Still might be, hopefully will know a bit more later after doing some basic diagnosing.

Is that TCC solenoid internal ?

 

When was the last time the plugs, cap/rotor and wires were replaced? Sounds like just a good tune up is in order if one hasn't been done in a long time.

 

Yes it is. Remember when you changed those wires in your tranny and I said you should also changed the TCC solenoid (the solenoids that connect to those wires you changed), well thats the TCC solenoid.

 

Could very well be.
I've changed plugs a few times, wires/cap & rotor are original to the truck AFAIK.

 

Those wires connect to the governor pressure sensor & solenoid, at least the harness terminates with connectors for both.
Now there are 2 more sensors that connect to them, maybe thats what you're referring to.
Those, I did put fresh ones in, they came with the harness.

 

id say dist. cap, when i took mine off when doing the plenum, there were i guess carbon deposits on the spark nodes. the rotor had it too.

Or the cap could be cracked. i bet it is just the cap, nothing big

 

OK, I would look into new wires, cap/rotor, IMO