Fuel economy problems

[ScottyB]

I recently got a new used car that was my dad's business vehicle, and I am experience fuel economy issues.

Right before I bought it, the check engine light came on and my dad took it to the shop. They said it needed new spark plugs and wires. A few weeks later, I took over the car, and it went from its normal 22 - 23 to about 12 mpg. We changed the plugs and wires and it seemed to fix the problem as I got 26 mpg on the way back home. However, the problem is still there. It seems when I drive the car from in one trip, I get really good fuel economy. When I drive the car over the period of a week or so, I get poor fuel economy.

I think that the problem may be the fuel pump or a leak in the tank or lines somewhere. But, before I go all gung ho about that, I wanted to know if I should try something else. I was looking at those fuel injection cleaners sold at department stores and I thought I might try one of them.

Any suggestions?

2006
Chrysler
Town & Country
3.3L
Basic
None
149,000

 

[boomerang]

Make, year, model, engine, miles and any history you know about would be helpful for me.

 

[ElFenix]

Originally posted by: Zenmervolt
Re-Stickied by popular demand.

When you post a question about your car, please post the following as well to help people make better recommendations and reduce the number of follow-up questions that we have to ask:

- Year
- Make
- Model
- Engine (if there are different engines available)
- Trim Level
- Modifications (if any)
- Mileage

By giving this information along with your question, we can tailor the response to your car and give you more accurate advice.

Thanks!

ZV

 

[ScottyB]

Originally posted by: ElFenix

Originally posted by: Zenmervolt
Re-Stickied by popular demand.

When you post a question about your car, please post the following as well to help people make better recommendations and reduce the number of follow-up questions that we have to ask:

- Year
- Make
- Model
- Engine (if there are different engines available)
- Trim Level
- Modifications (if any)
- Mileage

By giving this information along with your question, we can tailor the response to your car and give you more accurate advice.

Thanks!

ZV

2006
Chrysler
Town & Country
3.3L
Basic
None
149,000

 

[Bignate603]

If I had to take a random guess I'd say you might have an O2 sensor that's acting erratically. At 149,000 miles it really wouldn't be surprising to have them start to die.

 

[Vette73]

At 149k has it had the "100k" type service?

Plugs, wires, fuel filter, PCV valve, check air filter, change trans filter, front o2 sensors, and clean out the throttle body?

I know you said plugs and wires, what about the rest? You need to bring its maintaince to current level and if the problem is still there then you have something wrong. But the majority of the time when I had my shop it was basic stuff that caused a lot of problems like yours.

 

[ScottyB]

Originally posted by: Marlin1975
At 149k has it had the "100k" type service?

Plugs, wires, fuel filter, PCV valve, check air filter, change trans filter, front o2 sensors, and clean out the throttle body?

I know you said plugs and wires, what about the rest? You need to bring its maintaince to current level and if the problem is still there then you have something wrong. But the majority of the time when I had my shop it was basic stuff that caused a lot of problems like yours.

My dad had a tune up at 100,000 miles.

 

[Bignate603]

Originally posted by: ScottyB

Originally posted by: Marlin1975
At 149k has it had the "100k" type service?

Plugs, wires, fuel filter, PCV valve, check air filter, change trans filter, front o2 sensors, and clean out the throttle body?

I know you said plugs and wires, what about the rest? You need to bring its maintaince to current level and if the problem is still there then you have something wrong. But the majority of the time when I had my shop it was basic stuff that caused a lot of problems like yours.

My dad had a tune up at 100,000 miles.

What was involved in the tune up? That varies drastically from shop to shop.

 

[ScottyB]

Originally posted by: Bignate603

Originally posted by: ScottyB

Originally posted by: Marlin1975
At 149k has it had the "100k" type service?

Plugs, wires, fuel filter, PCV valve, check air filter, change trans filter, front o2 sensors, and clean out the throttle body?

I know you said plugs and wires, what about the rest? You need to bring its maintaince to current level and if the problem is still there then you have something wrong. But the majority of the time when I had my shop it was basic stuff that caused a lot of problems like yours.

My dad had a tune up at 100,000 miles.

What was involved in the tune up? That varies drastically from shop to shop.

I will have to check with him.