Some help Please. Im stumped, Thanks guys.

[240sxjoe92]

Alright so i have a 1991 240sx HB 144,405 miles on the motor. Problem is that the 4th cylinder keeps fouling the plug, car is burning some oil..Not all the time visible. The weird part of all this is. Sometimes when i start the car it runs like crap. Then other times it runs amazing. Example: Today i drove home from my church, Picked my dad up and the car started to run like complete A**, ran like that until i parked it at McDonald's..Went in got my food came out and started it, it ran amazing the whole way home. On the way to McDonald's it was running like s*** then cleared up for like 5 seconds. like went from running off ( what feels like 3 cyl ) to running perfect. Then just as fast as it came it went. But ran fine on the way home. It does it whenever it wants to. And im stumped. I know its not a HG cause there is no white smoke and no antifreeze and oil mixed. So please if you guys have any ideas or if you know what the problem is it would be greatly appreciated. Thanks guys for reading this i know people dont like to read alot so ill post some pics in here too.

[dfddfd2]

Fuel filter maybe?

[EnjoiNismo]

Fuel filter maybe?

Replace your fuel filter, putting in fuel injector cleaner wouldn't be a bad idea also.
Check the spark plug also.

[lrb_2000]

Is there any oil on the spark plug, or in the spark plug hole?

[240zac]

fuel injector might be stuck open... exact same thing happened to my car

same thing has happened to multiple people i know too... it seems that its common on ka's

[EnjoiNismo]

Ah yes My old KA used to do this, i forgot haha. Eventually one of my injectors clogged up and I had to replace it.

[ciscos13]

same happend to my sohc, never found out wat it was. lol

[240sxjoe92]

I've done fuel injector cleaner and fuel filter already. Didn't do anything. The plug keeps getting fouled im getting some new plugs tomorrow so ill take a pic of the old one that was in it and show you guys so that i can get further help with this issue. Thanks for all the help btw. And if it was an injector how would i go about testing the issue?

[OutToWinPAHC]

Is the plugged burnt? Could be an injector shutting off. Could be compression. Head gaskets dont always cause intermix.

[FolkertSX]

Today i drove home from my church...A**......s***

maybe thats your problem

[ciscos13]

check the plug that goes from the maf to the harness. make sure its pluged in right.

[Whitecar.]

I had a somewhat similar problem before and it turned out to be due to a leaky valve cover gasket, you should check and make sure the gasket around your plugs isn't ripped up.

[240sxjoe92]

Ok here are the plugs. ( Left-Perfect ) ( Right-Fouled )

[locoluna825]

whats your compression?????

[240sxjoe92]

Not yet...i haven't gotten ahold of a compression tester yet.