I really need to figure out what's wrong with my engine, but I have no idea where to start. I don't wanna get my head ripped off at a dealership and I don't know any reliable mechanics in my area, so I'm turning to you guys for some help

Engine:

87 LG4 V8.

Mods:

None that I know of.

Symptoms:

Burning oil - quite a bit. About a quart a week. No smoke, though.

Sputtering and hesitation - I noticed this the other week when going up the Cuestra grade by Pismo. I've been able to get it to do it a couple times since then. If the engine is under heavy load and below 2.5k RPM it hesitates. I don't mean slight. I mean, I honestly think it's going to shut off then it kicks back on and I can smell burnt oil.

Backfiring - only slight backfires when the engine is cold after lifting off the throttle. I really should leave for work sooner so I can let the engine warm up.

Sputtering and clunking - this is after the engine is turned off. And only occasionally. I can never guess when it'll do this and I can't reproduce it, so I can't even fathom what this might be.

Rough start - sometimes it takes about 20sec for the engine to start, but it doesn't die or anything once it catches. Only on a cold start, too, so I don't think this is a symptom.

That's about what I have going on. I was thinking oil leaking into the valve train, but I'm hoping it's not anything as severe as that. Thanks in advance for any help, guys.

 

Check your plugs for oil deposits. Oil deposits will look like a white chaulky "flag" on the ground electrode. Check the PCV valve for being plugged, check the PCV make up air tube for restriction, check the PCV passages in the intake manifold for restriction.

As for the back fire and hesitation, check your plug wires for stiffness and signs of age. If plugs and wires appear old and tired, perform a major tune(plugs, wires, cap and rotor, PCV valve and hose, fuel filter, air filter).

 

If you do find signs of oil fouling on the plugs and its not from a defective PVC valve or blocked breather system then you have either worn rings and or worn Cly walls or leaking intake valve seals or the cheapest problem would be a leaking intake gasket on the lifter valley side. If any of these are the case and you cant afford repairs you could install antifouling spark plug inserts. these do a decent job at slowing down the oil fouling but your plugs will still foul after some time.

 

to parrot what others say

absolutely plugs, wires, cap and rotor

after that, no more 87 octane. Stop using the stuff especially if you are going up grades

run at least 89

as for the oil consumption, inspecting your plugs will tell you and a compression test wouldn't hurt either

 

Sputtering and clunking after being turned off is known as deiseling, sounds like a timing issue.

 

Deiseling can also be caused by heavy combustion chamber deposits.