Misfiring under load after a oil pressure switch problem

[grim596]

Okay, got a new V6 Buick engine like 6 months ago and the it went fine for a good long while nothing went wrong with the actual engine
On thursday morning i degreased and sprayed the engine down (didn't drive)
Friday morning i had to leave newcastle to get to wollongong, so i left drove about 10kms and noticed the oil light on, pulled over turned out to be the filter wasn't on properly...
all good til i got to Bulli Pass, at the bottom it felt like she was losing power under load, not misfiring, pulled over and had a look, the pressure switch was pouring out oil, no warning light was on (???), so i got a new switch and some oil, all was good til the next morning and now it misfires under load

my question is what is a likely scenario that would cause each of those problems?

 

[grim596]

sparkies are fine, looks like there could have been oil splatters coming out the exhaust

 

[88GreenVN]

Missfire under load can be the leads - if all is good on the flat but when it comes to a hili it starts to miss fire cough and fart - I'd say the leads are shot.

 

[grim596]

I only just replaced the leads they're brand spankers... i know i have a problem with the spark in cylinder 1, checked it not long ago with a timing gun... but it wasn't this bad, it wasnt like it was missing or anything, just not sparking evenly

 

[grim596]

Still no idea whats happening, by the look of some posts on another site it could be a head gasket... anyone got some pointers, i've been meaning to do all the gaskets for a while and this seems like a really good time to get stuck into it

 

[88GreenVN]

Still no idea whats happening, by the look of some posts on another site it could be a head gasket... anyone got some pointers, i've been meaning to do all the gaskets for a while and this seems like a really good time to get stuck into it

Do you have milky coolant? - doubt this would be the issue, you could go to the trouble of changing all the gaskets and still have a miss fire under load.

Have you checked the ECU or DFI or Coils?

 

[LUMPY 8]

u sure u have the leads in the right order

 

[Not_An_Abba_Fan]

Could be just water shorting out the DFI or coils.

Remove the first two leads from the the first coil pack and start it. If the spark jumps from pin to pin then the coil is fine, if it goes down or anywhere else then the coil is stuffed. Repeat for all 3 coils and see how it goes.

(Taken from another thread, not my idea, but it worked for the mulligan-can)

 

[grim596]

i have oil bubbles in the coolant... but not milky.... pretty sure milky oil is the diagnosis for a really bad head gasket....

Leads are in the right order... lol!! i'm not that bad

i'll have a look at the Coils and EFI** pretty sure the Fuel injection is fine though... could be a gummed up injector.. hadn't thought of that til now

already have the intake manifold off and noticed the gasket has 2 major cracks on the back end... i'll dig a bit deeper but if i can't find anything i'll just replace that
I have a VY to drive around in until it's fixed... but it 's an auto XD

 

[delcowizzid]

most likely inlet manifold gaskets more than anything the head gaskets are pretty bullet proof