My 2010 Grand Caravan runs very rough when hot only.
I can start in the morning and it runs fine as far as I go (could be hours as in a couple days ago), but if I go somewhere, get back in and start hot; very rough idle and low speed operation. Once revs get up a bit higher it's a bit better.
Never happens when cold starting, never happens while driving.
Sometimes when it does run rough it will eventually go away, and it's sudden. Even while cruising you can feel that it is suddenly better.
Pretty sure the fuel mileage is bad, but I really don't track it.
Codes read are P205 and P305 with a cheapo reader.
I did a tune up (plugs and wires) last week, no change.
I'm thinking maybe #5 fuel injector is faulty???
Thoughts?
Thanks for reading.
Grant V

 

Bump... any thoughts?
Or should I just get it on a full tester?

 

The combination of those 2 codes most likely means the injector is at fault. You can verify it by swapping the injector to another cylinder and see if the codes follow it. You can also try measuring resistance of the injectors when the fault is present- I don’t know the specification off the top of my head, but the faulty injector will have a significantly higher or lower reading than the others.

You’ll also want to inspect the wiring and connectors for damage.

 

Thanks for the reply! Would definitely check wiring while it's all apart.
Any idea how long to swap/replace a fuel injector? First timer, but not a novice at auto work. I'm thinking it makes more sense, if it's a few hours particularly, to just get a new injector while tearing it apart. Was thinking I'd buy one new one, put it in a different cylinder and that cylinder's old one in #5. Just more reassurance if it happens still/again, that it will read #5 if wiring/connections, or where the new injector is (in the 1 in 1000 chance the new injector is faulty).

 

If it’s a 3.3 or 3.8 engine, the injectors can be swapped inside a couple hours. They’re pretty simple engines on the top end. Just make sure to have new upper intake gaskets and o-rings for the injectors on hand as you’ll probably need to replace them.

I don’t recommend swapping them as you’re describing simply because you don’t know yet why the injector failed. The point of swapping them between cylinders before installing a new one is to determine if it’s the injector or wiring/control - if the injector from #5 moves to another cylinder and the misfire remains on #5, then the diagnosis needs to shift to wiring and the PCM because there’s not actually anything wrong with the injector. But if it moves to cylinder 2 (for example) and cylinder 2 starts misfiring, the injector is the issue.

The point is to avoid replacing components unnecessarily.

 

3.3
My reasoning was only in the slightest case of the new injector being faulty.
Assuming #2 as you said:
New injector on #2, proven #2 injector on #5. If the new injector was faulty (heard of this being not rare), and #5 reads bad still, it's pretty much guaranteed to be wiring. If one installed a new but unknown to be faulty injector in #5, you'd not know where the issue is. Make sense?
Your replies are appreciated!
Any idea where is best to buy parts? ...in Canada? 🤔

 

I understand your reason for concern over the new injector being faulty, but that's all the more reason to swap them between cylinders before replacing one. Taking an injector from a cylinder that isn't misfiring is essentially the same as installing a new one - you have one known good injector and one suspected faulty injector. You'd end up doing the same if you installed a new injector that you suspected to be faulty, so save yourself the effort and skip the extra time that would be involved unnecessarily.

I'm not familiar with Canandian parts stores - not everybody has good things to say about it, but I've had good luck with rockauto.com - I've ordered from them several times and haven't had trouble with any of the parts I've received.