Stock 1998 tA running rough

[1998ls1tA]

Hi, my 1998 tA is running rough it sounds like it's choking even at idle it shuts off and when I press on the gas it hesitates and starts to choke and wants to shut off I can't even drive it around the block that's how bad it's running I need help bad , I have a new mass air flow sensor , air filter , just gave it an oil change and zmax but it's still rounding rough and is smoking just abit and smells abit rich

[SMWS6TA]

ok disconnect the new MAF and start it. see if it idles better (it may have a slightly higher idle, that's ok).

Is the new MAF an OEM replacement or aftermarket?

[initechpeter]

Why did you replace the MAF? Try re-installing the old one?

[0rion]

have you checked the fuel pressure?

[1998ls1tA]

It is an OEM replacement it ran better when I replaced it but the problem came back and I haven't checked the fuel pressure

[1998ls1tA]

And it would not stay running once I unhooked the MAF

[pajeff02]

Do you have the stock catalytic converters on the car? Is the SES light on?

[SMWS6TA]

Also what color is the smoke? White or dark?

[1998ls1tA]

Yes they are stock catalytic converters and there are no lights on and the smoke is white

[pajeff02]

As a general rule - white smoke is coolant, black smoke is fuel and blue smoke is oil. Do you notice a sweet smell (like antifreeze) from the exhaust?

[1998ls1tA]

It looks kinda blue and it smells like oil burning

[pajeff02]

Any knocking or ticking sounds?

[SMWS6TA]

best to do a compression check with white smoke

[1998ls1tA]

No there's no noise coming from the motor

[SMWS6TA]

Doesn't need to have noise to have a head gasket leak. Compression check is cheap insurance and test to make sure. Autozone will rent you the tool and when you return get your money back.

So they are the original Cats, correct? Clogged CATS WILL cause running issues.


Also have you checked the fuel pressure at the rail (drivers side) like Orion posted? At idle it should be around 56psi. Also another test is have someone turn key one click to let the fuel pressurized the line and see if it holds pressure or decreases.

If the pressure decreases or is not at around 56 psi @ idle - you'll need to start looking at the fuel pump or regulator. Change the fuel filter first if have not already.

[0rion]

check the pcv line where it turns to go into the intake for a crack, check all other vacuum lines for leaks, check for exhaust leaks before the front O2 sensors, and check fuel pressure. Those are the first steps I would do. Does it run rough at first start up or does it start after the engine has been running a few minutes?

[Knight]

Agree with Orion. Make sure you didn't accidentally disconnect any spark plug or coil wires too.