The car has a 3.1 V6 with 127,000. Last month the intake gasket blew on the top, right hand side of the motor. It'* my girlfriends car. Is that the right motor size? V6 4 sure.

A month later the car is bucky and jerking whenever you give it gas and sometimes just cruising.

Could the gasket job have done something to make it misfire. It'* flashing 3 codes. PO303 PO 336 PO440

I don't know when the plugs and wires or if they were ever changed. There is also a tapping noise. Valve or something. Could the valve noise make the #3 cylinder misfire?

I put in dry gas and injector cleaner. Haven't driven it too far yet. Auto parts guy said make sure we don't plug up the catalytic converter.

Could antifreeze somehow haved fouled the plugs?

Thanks ahead of time.

You have a 3800, not a 3.1.

Did the car leak coolant externally? Or, was it an internal leak?

I'm wondering about them plugs, wires and coil packs.
Start with changing the plugs and wires, and check out Tech Info on how to check the primary and secondary resistance on your coil packs. My car did a similar bucking problem, and it was one of the coils.

Also, please update your signature with year and trim level of your car so the experts know what you are working on.

Good Luck,
Adam

Outside leaking for sure. Inside I don't know. It happened 250 miles from home. We left it to get fixed and went back to get it. So do I really know what else happened to it, no. The mechanic worked in a used car lot. What his level of expertise is.... but the owner sent his guys in the car to meet us. They drove it 2 hours through the mountains to get there. He changed the oil and made sure it could make the trip. I'm sure he didn't want to pay a tow truck.

Could his guy maybe have bumped some wires or connections during the operation? Did he swap any parts on me? Who knows. I gave him $100 for parts and $200 labor. We didn't get an itemised bill. Just glad to get it back in one piece.

I need to check the vacuum hoses. Should I do the fuel filter yet? What about the tapping noise. The oil level is good and clean. There is probably 4-500 miles on it since it was fixed. Could a valve be bent and making noise? That would cause a misfire, yes? Not sealing tight.

It just started acting funny a in the last week. The car has been home for a month now. Bad gas, clogged filter? Girlfriend won't listen to me about buying good gas at the same station (company) regularly. I always use BP mid grade and never have any problems. I tell her to get mid grade but whether she does or not, and I know she doesn't always buy BP. I tell her "buy cheap gas and buy yourself problems."

Do you recommend a certain brand of plugs and wires? A buddy of mine owns a junk yard. Will the coil packs from another year fit the 98?

May be unrelated to the gasket blowing... but I had my O2 go bad and it had similar symptoms.

Code PO336 is crankshaft position sensor. Other than the sensor itself, can anything else give that code? Or cause that code? Would that cause it to misfire?

Start with plugs and wires.
Our cars don NOT like BOSCH products, so stay away from those.
Belden wires, and AC Delco plugs seem to be the fav'*.

You might get lucky!
As far as coil swapping, check your local auto parts gurus and they can tell you what years the packs have been used.
Do the test first using your voltage meter as shown in Tech Info.

Adam

When it says misfire, does that mean it'* firing once in a while or not at all.

So you suggest wires and plugs and have the codes cleared to see what happens?

Start with the easy stuff.
If a plug is fouled, it could be firing once in a while, or worse yet, not at all and merely along for the ride.
For the amount plugs and wires cost, it'* the easiest and most cost efficient place to start.