My 1997 grand am runs rough, theres oil around the 1 spark plug, if it sits and runs for a 10-15 min it will start to get hot. also the gas gauge will say 1/2 tank then after a mile or 2 it will say 1/4 of a tank, then stop, turn the engine off wait 10 min start it up again it will say1/2 tank again.

Clean the engine well and look for source of leak, one place is oil pressure sending unit. try Marvel Mystery Oil in fuel tank to help free sticking fuel gauge sending unit. Stuck spark plug is bad if in aluminum head. Spray PB Blaster around plug several times after engine is warm and let sit. I have had cross threaded and corroded plugs take out the threads in the head have had to insert helicoil to repair it. Try removing the plugs when the engine is hot, aluminum expands when hot.

spark plugs or a loose wire.

Check for spark on a plug wire when it won't start. If no spark until it cools down, the ignition system is the problem. Could be the coil, the ignition control module (igniter), a crank sensor or pick-up coil, depending on your system, ...some of the most common things to check. If it just stalls, likely lost spark or gas to the engine cylinders. With a new pump, it probably lost spark.

valve seals worn out they get hard 4 and 8 cylinder is very close must be from head gasket oil going to the cylinders do one petrol treatment for 2 times and one oil treatment flush. New oil filter and oil fit one size up more hot spark plugs check the pcv valve for mail function clean fuel tank and fuel filter new.

My van cuts off after driving on a long stretch of highway. Around town it does pretty good. It starts back up after ten or fifteen mins. I changed the oil, oil filter, coil pack new spark plugs, and fuel fliter. It still does it. Does any one know what this could be???? O its a 2001 dodge caravan

check the cables of the spark plugs, some times it occurs that the cables get loose from its plastic retainers and touch any metal in the engine, causing missfire of the related spark plug, hence rough running of the engine. Put all cables on the retainers making sure none touches the bare metal of the engine. That should help.

is there smoke coming out of the exhaust? if so what color? if it has white smoke is usually a blown head gasket. if it is a bluish gray it is oil. check your radiator when it is cool. if it appears to have oil in it it could be a blown head gasket. if you leave the radiator cap off start the motor, if you rev the engine and coolant shoots out of the radiator (compression from the cylinder forcing water out) it is a blown head gasket. this can cause the motor to run weak and idle rough and oil to disappear.
if you happen to have a compression gauge take out all of the spark plugs look at the spark plugs if they all look the same or is there ones that look black and sooty(running rich) or looks green(burning antifreeze/water) white Burning hot) http://www.dansmc.com/spark_plugs/spark_plugs_catalog.html
check the compression of each cylinder it is easier if you have an assistant for this. place the gauge over the spark plug hole crank the motor once or twice. the gauge should be around 120 psi (pounds per square inch). if all of the cylinders are under 120 psi more than likely you have worn or broken rings which will cause low compression causing it to run weak and consume oil.

Check the primary and secondary resistance on your coil and resistance and gap on your spark plugs. Sounds like you have a high temp foul out.

You will need to do a fuel pump pressure check. You will need to borrow a gauge or purchase one ($40 to $50), attach it to the fuel injector rail test port, it will have a little black cap on it, turn the key to the run position. Your fuel pressure should be in the range of 45 to 55 lbs.

The knocking noise is a little peculiar, check the engine oil for proper level and smell the dip stick. It may smell like gas, if it does, change the oil immediately. The gasoline has diluted the oil and is to thin, causing the knock.
Let me know.
Regards,

install a fresh set of plugs. make sure to check them for proper gap, even if they are " pre-gapped "


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