Car Trouble (Need Help)

[Ash]

This question is for those of you who know a thing or two about cars.

Last night I drove to a friend's house and my car ran fine on the way there.
When I got into it to leave, I started it up and immediately noticed that the engine sounded different.

Here are the symptoms:

1.) The engine makes a deep "flapping" sound.  When I step on the gas, it sounds almost like a helicopter.

2.) The engine seems to have half the power it should.  I have to press the gas pedal down much further to get the same amount of power than before it started acting up.

3.) The combo smell of gas and exhaust are almost overpowering inside my car.  It is so strong, I have to have the windows down while driving.

4.) Sometimes I can drive for several blocks and the engine will run normally.  But it will eventually start that flapping noise and drop in power.

My car has ran fine for years until now.
Anyone know what the problem might be?

[trekgeezer]

I don't know for sure Ash, but the gas smell isn't a good thing.  Maybe it's something with the fuel system.

[Trevor]

If you have a drop in power in your engine Ash, I suspect either problems with spark plugs and/or the leads going from them to the distributor.

Trek is right about the fuel system though: have it checked asap because it could let you down when you least need to be let down. If your fuel lines are blocked in some way, that could lead to the gas smell you have.

[Trevor]

I just remembered that I had this same problem with my Toyota pickup several years back. The noise I had was very similar to yours: it sounded as if my Toyota had suddenly become a VW Beetle and there was a rrrrrrrrrr noise as well as a major power fall off.

The mechanic that worked on my car replaced all four spark plugs and all three leads and the problem went away, never to return.

I'm actually rather  about just talking about my old friend: she gets sold tomorrow and she was my first car. 

[Jack]

My guess would be that the engine's running way too rich (too much fuel in the fuel/air mixture).  That will cause the drop in performance and the gas smell, it's half flooded.  The fuel/air mixture is controlled by the computer and its myriad of sensors.  Could be any number of them.  The fact that it occasionally runs okay points to something in the computer/sensor system, most mechanical causes would be more-or-less constant (from my internet analysis).  Could also be that it's got your timing all screwed up, if the plugs are firing at the wrong time it produces essentially the same result.

My first guess would be the oxygen sensor, it controls the fuel/air mixture by sensing the amount of unburned fuel in the exhaust gasses.  When it goes out it typically sets the mixture way too rich.  Could be other things though, that's just a guess. 

Of course it could be something simple, like one of your spark plug wires came loose or developed an internal crack in the conductor, so it's making contact sometimes but not most of the time.

[AndyC]

I think Trevor has it right. The uneven running, the drop in power and the unburned fuel smell all sound like you have a cylinder that isn't firing. If the problem comes and goes, I would guess it's a bad ignition wire. Does it backfire at all?

[CheezeFlixz]

I would check for a bad or loose plug wire, bad plug or a bad distributor or loose distributor cap. It sounds to me like your not firing on all cylinders. Seriously, that's what it sounds like, rule of thumb when fixing any problem that JUST appears out of the blue, look for the stupid stuff first. I don't think it's a computer problem because it comes and goes, sensors and electronic problem tend to go and stay gone until fixed. O2 sensors will normally only result in a check engine light as with most electronic problems, if you do not have a check engine light I'd start checking for loose connections. Again if it's a time belt it would be constant and no come and go, generally with a timing belt issue it will not run at all.

Since I do not know what kind of car you have, nor how regularly you have it serviced or how well you keep the maintenance up on it, the best I can do is guess.

If it is not firing correctly, you need to get it fixed. It can and will cause engine damage over time, not to mention get really crappy MPG. Not firing correctly results in unburned gas and the gas smell.

[odinn7]

I was a mechanic for 15 years and the symptoms you're describing fit a miss in the engine like others have said. Bad wire, bad plug...perhaps a coil pack going bad (depending on your car).

Was it raining at all before or during your problem? If so, check the wires first.

[Patient7]

In my opinion, you need a new Johnson Rod.

I feel sorry for those of you who don't get the reference.

[Sister Grace]

i had this problem. my last car done this for a few days before the fuel injection went out in it. Check it, because if that is the case, it may catch fire...

[Ash]

I still haven't gotten it fixed yet.

Since I'm not a car guy, please enlighten me.
How does a bad plug or a problem with the distributor make my engine not fire on all cylinders?   

Educate me...

[Trevor]

I was always told that the spark from the plug travels up the wire to the distributor, which sends it to the cylinders: the current generated ignites the petrol there and drives the car forward. 

[AndyC]

Not exactly. The ignition module produces high voltage, which is carried by the wire to the plug, generating an arc that ignites the fuel-air mixture. Plug no spark, cylinder no fire. The unburned fuel would also account for the gasoline smell. Most likely cause, particularly if the problem is intermittent, is a loose or faulty ignition wire.

You should probably get it looked at. Unburned fuel in the exhaust can make a mess of your catalytic converter.

[CheezeFlixz]

I still haven't gotten it fixed yet.

Since I'm not a car guy, please enlighten me.
How does a bad plug or a problem with the distributor make my engine not fire on all cylinders?   

Educate me...

The distributor, distributes the electrical power to the plugs via the plug wires, the plugs fire in a sequence, When the plug fires it burns the gas causing a explosion pushing the cylinder down, making the cam turn to make the wheels go round. thus which wire is where is VERY important. If a wire is bad, loose, etc it will not fire or will fire intermittently. This will cause the car to run rough, and leave fuel unburnt causing gas smells.




I would first check one of the wires, the BLUE LINES in the image above.

VERY IMPORTANT -- if you change the wires, and you are new to this, change them ONE AT A TIME!!! If you get them mixed up your car MIGHT run not very well. The plugs MUST fire in correct sequence. They are not set up 1,2,3,4 etc ...

[Ash]

I had my dad check the spark plugs and plug wires and they were all fine.
(he replaced the plugs anyway)

After some routine tune-up stuff, the problem still wasn't fixed.
Turns out it's the ignition coil.
It seems that 1991 Geo Prizms are known for having bad ignition coils and my car is no exception.

The ignition coil for my car runs around $100 but my dad can get it for cost for around $50.
(he owns his own auto repair shop)

Unfortunately, I wasn't able to attend the Troll 2 screening in Chicago because of it.
I couldn't run the risk of that coil going out while on the road.

My dad said to me, "If that coil goes out while you're on the road, you're going to be stuck where you're at.  You're travelling to the third largest city in the US and you need a reliable vehicle to do that.  I'm telling you right now to not drive this car out of town."

So I followed his advice and didn't drive to Chicago.

It sucks because other than trouble with the exhaust, I've had no problems at all with my car.  

So now I've got to come up with the cash to get it fixed.




P.S.  I gave karma to everyone who replied to this thread.  Thanks for the help and advice.