ecotec v6 missing/struggling/backfire under load - any ideas?

[Heffer_Slayer]

Hey all,
Took my grandad's v6 statesman for a drive, and noticed it misses under load/heavy acceleration. It feels like the engine moves around violently as if its the trans but due to the backfiring i dont think its the transmission, just thats the way it feels.
Few examples would be;
Cruising on the high way in 4th, accelerate a tiny bit and it would start "missing" sometimes backfire (not loud due to stock exhaust). This is when it feels like the transmission but I doubt it due to the second example and the backfires heard.
or you plant it, it wont rev up freely and kind of struggle around the 3000rpm + mark. It will still rev out, just kinda stutter along the way.

Unsure what to do in terms of trouble shooting, any idea's fellas?

Can cruise around fine on light throttle unless its in 4th low down. Click it back to third with light throttle and generally its fine, but as stated it happens if u give it the boot too. Can make taking off in a hurry a bit scary!

 

[Brett_jjj]

It sounds like its misfiring when its under load, a fairly common problem when certain parts get old and worn, and it can be hard to diagnose as they will still run ok when theres no load on the engine.. Replace the sparkplugs and plug leads first, and if no better, replace the 3 ignition coils with genuine holden coils.

 

[Heffer_Slayer]

Cheers Brett, The leads look fairly new, but the old pop aint too sure when they were last changed.

Any way to isolate the issue other then throwing money at - ie replacing maintenance items it in hope it fix's the issue.

 

[Brett_jjj]

Not really, not without spending money on more parts, unless you can borrow known working parts from someone and try them to see if it fixes it. But if the leads etc on the car are more than a year or two old, then its probably best to just replace them for starters, as they will be the likely cause of the problem. With the high ignition voltages these EFI systems run these days, plug leads dont last for years like they did with the old points and coil type ignition systems. When was the fuel filter last changed ?

 

[Heffer_Slayer]

Unfortunately can't tell you much about the cars history being it not mine, and grandpa aint too good with motor maintenance.

Hopefully I can get his approval to do some maintenance on the old girl.

 

[Wozza]

Hi
you could try cleaning and regapping the plugs if it improves a bit then your on the right track,also sometimes you can see faulty leads at night if very dark, it will look like little glow worms running through your leads

 

[Not_An_Abba_Fan]

Missing under load is a common lead fault. I would change them.

You could also do an error code check to see if it has logged any codes and go from there.

 

[benny_bones]

Change leads and plugs then look at 02 sensors after that

 

[Heffer_Slayer]

How do I check for error codes?

While Ive got the thread open, The fuel gauge seems to intermittently work, give the dash a tap and it literally springs back to life ha ha. I have done some searching on that issue though, and apparantly its just dry solder. A resolder on the dash connections and it works again.
Another issue is the fuel light comes on every time, no matter how much fuel is in the tank. The light that beeps at you saying your low on fuel.
Any thoughts on the beeping fuel light?

 

[Nathan kenny]

I have a 96 vs commie I went to the car wash yesterday and clean the engine after I left i drove out and the car started to splatter and still doing it