Coughing and choking

[Ckirkhoff]

Hi all...

I have a problem with my VS III V6 Ecotech ute.
It is coughing and choking when I put the accelerator halfway down or if I go up a hill or anything that require the car to pull a bit harder.
It seems to slowly get worse and worse. Also a little more noticeable when it has warmed up.
It doesn't come up with any error codes and I know it is not the gearbox, cause it makes choking notices when pumping the accelerator in Neutral.
So far I changed the fuel filter, air filter, leads, spark plugs and o2 sensors. So all the cheap option are done ;-)
I did some research on the net and this forum in particular, so I think I have nailed it down to be one of the following parts:

• Fuel regulator
• CAS
• DFI and coils
• Throttle body

When I changed the fuel filter I noticed it was pulling hard and no choking, so I thought it fixed the problem, but when it warmed up it was back. Just feeling it was going great for a moment makes me think that it can't be a bad cylinder compression. And also... Wouldn't that eliminate the DFI and the CAS? Wouldn't they either work or not work?
I might add that the other day the Engine fuse blew. I replaced it and it was fine. Don't know if that makes the diagnosis easier.

What are your thoughts, what would you change next. I am starting to have to change more expensive parts and would like to try not to change all the working parts.
Hope anyone can help me with this little problem.

 

[AA6]

Id say electrical system. I would check the coil packs out, see if you can borrow some known good ones and swap them in if you can. I doubt the throttle body or fuel reg would get worse with engine temp, and I think the crank angle sensor just cuts the motor entirely.

 

[jgtoranalc]

I agree with AA6... next I would also check the coil packs... you could check the specs of them or simply replace them..... unless you have a mate with the same engine and swap

 

[Ckirkhoff]

Just went for breakfast this morning and while driving down there I notice that it still runs really well when it is cold. Obviously can't push it too hard with a cold engine. But it is 100% better than when it's warmed up.
I don't know anyone with the same engine, so I decided to take your advice and get a replacement coil pack with dfi. Will when I get it home.
Someone told me it could be the air flow meter too, but wouldn't that either work all the time or not at all?
Cheers

 

[Ckirkhoff]

*Will update when I get it home.

 

[jgtoranalc]

People usually say to replace the Coolant Temp Sensor...but I wouldn't think it would cause it to "cough". Usually I think it would just effect Idle.

 

[AA6]

After I washed my engine I had a misfire problem under load, it slowly got better and only happened when warmed up. I ended up changing the coil packs after a while, which fixed it, but maybe it would have got better if I waited longer? I dont know.

 

[adam10_1990]

It would have just been residual moisture in and around your coils shorting them out, reducing the spark. When i wash my engine i normally pull the coils out, spray wd40 on them and then clean it of with a rag.

 

[Ckirkhoff]

Hey guys...

You were right, it was the coil pack. I got a $50 one from a wrecker and it is pulling fine now. It just seem to be running with more vibrations now than before. The coil pack I got was from a VR, and I just put the coils onto VS dfi.
Correct me if I am wrong, but aren't the coils from the VR identical with VS?
At least I know what is wrong now and maybe I can get so e new ones instead if I feel I need to, so thank you so much guys. Appreciate your help.

 

[v6nutz_2012]

Hey guys...

You were right, it was the coil pack. I got a $50 one from a wrecker and it is pulling fine now. It just seem to be running with more vibrations now than before. The coil pack I got was from a VR, and I just put the coils onto VS dfi.
Correct me if I am wrong, but aren't the coils from the VR identical with VS?
At least I know what is wrong now and maybe I can get so e new ones instead if I feel I need to, so thank you so much guys. Appreciate your help.

All coil packs from VP S2 to VY are the same