Impossible to diagnose virtually, especially without more info.
A few maintenance items we did to tune up the Regal LS 3800. These made the car run smoother, quieter and more responsively. The car started faster also. Your issues may differ so no guarantee lol. Be really careful with battery, power, fuel, explosions!
- Make sure you are getting max power to starter and plugs (video below and quote are a good start)
-- Clean battery terminals, battery clamps, and trace those wires to clean terminals, alternator wire, body ground, engine ground, etc.
-- Check voltage of battery at off, at idle, at idle with lots of accessories on. Also check your grounds to body, engine, alternator, starter in those scenarios.
-- Have Interstate Battery or another auto parts store check your battery, alternator, starter
- Replace air filter
- Clean MAF (special MAF spray only)
- Clean throttle body, both sides & edges of butterfly. Also clean the tube that contacts butterfly valve (special TB spray only)
- Gap and replace spark plugs & wires. As rear plugs are difficult to reach, buy expensive platinum plugs & expensive wires
- Remove and clean EGR valve. With valve removed we turn over the engine a few times to blow some carbon out. Clean old gasket material and replace with new gasket
- Look for any vacuum leaks and resolve
- Use some premium fuel for a few tanks from a major gasoline supplier (e.g. Exxon or Shell)
- Add a bottle of fuel injector cleaner to fuel
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This was in the comments from a Wayne P:
"working on cars.. voltage drop testing do you have a digital voltmeter..set it to 20 volts DC. engine off.. headlights on for one minute. then turned off.. check battery voltage.. 12.65 is a fully charged battery. 12.45 is a 3/4 charged battery. 12.25 is a 1/2 charged battery. if you have less than 12.5 volts have your battery charged and load tested.. once you verify that the battery is close to a full charge after you have removed the surface charge with the headlights on trick... get the engine started... turn the headlights back on.. Negative battery post to the positive battery post.. 14.1 to 14.8 volts is expected.. Negative battery post to the engine block. 0.04 volts DC MAX.. Negative battery post to the body of the car.. 0.02 volts DC MAX. Engine block to the Body.. 0.02 volts DC. if you get more than the 0.04 or 0.02 volts on tests 2, 3 or 4.. you have a bad ground connection.. you can and should also.. after running the voltage drop test above.. test from the battery post to the alternator output terminal.. because of the amount of output.. i normally expect this to be up around 0.07 volts.. "
