First, this car has been sitting for atleast 3-4 years. I brought this car off my boss. He's sat the car for a long time because the back driver sids strut broke. I mean completely in half and it's been sitting since. The car starts up fine, but, it has a little misfire going. I've finally got around to changing some parts. I've changed the broken strut, replaced all the tires, oil change, air filter, brakes also, and when I gotten to the spark plugs, I guess the #4 spark plugs "the rear middle one" was just a little bit wet on the tip. Just a very little bit. All the rest of the spark plugs were dry except this one. Is that normal? I hook up my obd2 scanner and gotten the p0300 and p1105. The crazy thing about the p1105, I've changed the map pressure switch solenoid valve and im still getting the same error code. All plugs are ngk platinum. What should I do about the p0300 and the p1105 especially since I changed the part? What should I change on the car period since it's been sitting for so long? Any help will be appreciated. Thanks

 

Since the car has been sitting 3 to 4 years, most likely the injector o-rings dried out and are are now leaking. We see a lot of leaking injector o-rings as our cars start to reach 20+ years of service. Injector o-rings are just another rubber item that deteriorates with age -- like hoses and belts. Please search on injector o-rings to see stories about leaking injectors that have been posted since 2013.

When you say the #4 plug is "wet on the tip" are you talking about wet with fuel?

Code P0300 - Random Misfire Code Possible Causes

Faulty spark plug (s)
Faulty ignition coil (s)
Clogged or faulty fuel injector (s)
Intake air leak
Fuel injectors harness is open or shorted
Fuel Injectors circuit poor electrical connection
Ignition coils harness is open or shorted
Ignition coils circuit poor electrical connection
Insufficient cylinders compression
Incorrect fuel pressure

For code P1105 - here's a video on how to test and replace the map baro switch.

 

The middle rear plug wetness could be a leaking injector, as CS_AR said. He is our forUm expert on this subject.

Fixing the problem will require removing the uper intake manifold. This is not particularly fun.

These cars have other issues which live under the intake manifold. Please look up the clogged egr tube and how to deal with it. Much easier whole the uim is out of the way. The knock sensor lives under there. This would be a good opportunity to replace it. Coolant hoses you find will be due for replacement as well.

Consider rebuilding the injectors, at least the rear ones. Or you will be removing the upper intake manifold again, and soon.

 

I think air is getting in from the intake manifold area. It sounds like there's a hole in that area when I step on the gas.

 

Check for a loose vaccuum hose. Or more than one of them.

 

Why am i still getting the p1105 code when I just replaced it with a new one?

 

Is there a chance a rodent could have chewed on some of the electrical lines while the car was sitting all those years?

My latest 4th gen restoration project is on a car that sat for a few months. I can see where some type of varmint took up residence in the engine compartment and chewed on various parts of the wiring harness.

So I will be replacing some chewed up wiring very soon.

As JVG suggested, I would check for leaking vacuum lines also.

 

The car was sitting at a business. If the rodents chewed threw electrical lines, I wouldn't be abke to drive it correct? I drove it around town. It drove bad, but, it still drives...

 

It would still run, drive, and throw codes due to electrical faults. What I want to say is you may need to do some electrical testing to determine if an electrical contact is breaking down somewhere that is behind the map baro code.

Several years ago, I bought a low miles Q45 that was driven at least once or twice a month. Soon after I bought it I found a rodent had chewed up the knock sensor harness. It happens..

Where did you get the replacement map baro switch?

 

I gotten it from ebay. Could it be bad too or can it be the vacuum lines connected to it?

 

Could be vaccuum lines or wiring.

Keep in mind. . A code can mean that a particular system, including wires and hoses has an issue.
It's possible that the part which is commonly replaced when a code comes up still works perfectly.

 

What else should I look into replacing? The wet spark plug, should I replace the ignition coil to that spark plug?

 

If the plug is wet and smells like gasoline, the problem is a leaking fuel injector.

Replacing the plug or the coil will not solve thus issue.

It would only do that if the plug was mis firing.

Knowing how likely it is for an injector to leak on these cars, check there first. Otherwise you will spend needless money first, before you fix the injector.

 

That's the thing, I don't know if it was gas or oil on the tip of the plug. Should I just change the injector o ring on that plug?

 

Replacing the o rings on the injector will not solve the problem. The pintil cap cracks. It is a plastic bit which holds the sprayer screen in place.

Once the pintil cap cracks, excessive fuel leaks through the injector.

The solution could be a new or rebuilt injector.

There are rebuild kits available if you want to do your own work.

I sent my injectors to InjectorRX in Houston.

They do ultrasonic cleaning, flow balancing, and rebuild the injector. I was happy with the tesults.

 

Thanks.Would a bad ignition switch cause any problems?

 

Any bad part could cause problems. The ignition switch is an electric switch. If the switch is bad, it will not make the electrical connection and something is not going to work. One of the more common problems with the ignition switch is that the car will not start. You turn the key and... nothing.

What kind of problem are you having?

 

I finally fixed the p0300 and p1105 problems. The ignition coil was bad on cylinder #1 and the vacuum was off of the other end of the maf solenoid valve. My ignition switch is bad because it starts up fine all the time but, sometimes I've to turn the key a little forward for the the radio and windshield wipers to come in.

 

Do a search on the ignition switch, most likely the ignition switch wiring harness interface connector is worn. You can replace the harness (pretty easy), or even just use electrical tape on the ignition switch interface part to reduce the gap. If you search, you will find many threads on this subject. Most likely, your ignition switch is not bad.

Do a little homework and you should be able to fix this problem without too much effort or cost.
Good luck