INSPECTIONS & EMISSIONS

Some states require regular safety inspections and/or emissions inspections on cars and trucks. At Dow's Automotive Service, we are well-equipped and trained to perform these inspections. Our technicians can also perform multi-point inspections on your vehicles as needed.

These are some of the inspection services we offer.

NH State Inspection Station
NH state inspection stations are privately owned, but government certified, inspection stations throughout NH. Dow's Automotive Service is a NH state inspection station. For your state inspection needs visit or call our auto shop at 603-436-9886.

Exhaust Questions and Answers

Q: What is a rough idle?

A: A rough idle describes a vehicle's engine with spark plugs that are not firing correctly when the vehicle is in park, with no gas applied. Most vehicles idle between 600 and 1,200 RPM and should hold their idle speed consistently.

Q: Why is smoke coming out of my tailpipe?

A: The most common reason for thick smoke coming out of your car's exhaust pipe is the fuel to air ratio in your engine is too rich. This means that the fuel injectors are either adding too much fuel or that the intake valves aren't letting enough air in. This is caused by a cracked or leaking fuel injector, a failing O2 sensor, or air filter that needs replacing.

Catalytic Converter Questions and Answers

Q: Can I drive with the catalytic converter light on?

A: A bad catalytic converter can increase your car's exhaust emissions, but it does not prevent you from driving. At Dow's Automotive Service we know this is true. A clogged catalytic converter will eventually affect the performance of your vehicle in Portsmouth, Newcastle, Greenland and Stratham. Exhaust gases will not escape easily and create an increase in exhaust gas pressure. The buildup in pressure can lead to high-cost repair bills in the future.

Q: What can cause a catalytic converter light to come on?

A: A catalytic converter helps reduce harmful engine emissions from entering the air by breaking down the harmful byproduct of internal combustion into less-harmful compounds. If your catalytic converter isn't working properly the check engine light will come on. The most common causes for a catalytic convert warning light to display are a clogged, cracked or melted converter. Sometimes the problem isn't the catalytic converter at all but an exhaust leak letting gases out of the system before it reaches the converter.