Question I have a 1970 Pontiac Firebird with the original rebuilt 350 motor. I only drive the car once every other week for about 15 miles. All of sudden today the car stalled a few times and also backfired a few times. The car started up after the stall every time and one minute it was running fine but the next minute I was losing acceleration and then it would either stall or backfire. Where do you think I should begin?
Answer Well there are only three things that an engine needs to run well, compression, fuel, and spark. I would probably start with the ignition system checking the points and the point gap. I would check the breaker plate for wear. If this is worn then the car will act like you are describing. The pig tail wire in the distributor that connects the point to the = side of the coil could also be defective giving this symptom as well. If the ignition is OK then on the fuel system especially the fuel filter if the engine only acts up whe accelerating or at road speed. If the fuel filter is ok then I would take a fuel pump pressure test and a fuel pump volume test and finally I would take the top off the carburetor to check foe water and dirt in the float bowl. If you take the carburetor off the engine foe service don't make the common mistake of turning the carburetor over and draining the gas out of it before you start to work on it. Keep it upright so that the fuel remains in the float bowl and you can either see the bottom of the bowl and the condition of the fuel. I run a carburetor rebuild shop. I tell my customers to bring me the carburetor in with fuel in them. I then take the top off and drain the fuel into a glass jar, then put the lid on and set it on the shelf for a few minutes. This allows any water and dirt to settle out to the bottom of the jar. You would be surprised at what I often find. Then I can advise the customer what realy needs to be done.
All automotive including antique and collectible. However if the car has been modified I can only answer in general terms and maybe get you pointed in the right direction.
Automotive tech instructor.
Syndicated auto columnist 1970's though the early 1990's.
Syndicated auto radio talk show, Ask Brad About cars, CBS Radio 70's through 90's
TV Show "Last Chance Garage" 1980's PBS-TV syndicated.
Auto instructor for the following companies:
University Of Conn
Blue Hills Technical School
Sugar River Technical Center
Grew up in a family garage in Needham Mass and turned wrenches from the age of 14.
Publications Manchester Union Leader, Nashua Telegraph, Motor Service Magazine, Yankee Magazine, Popular Mechanics (Saturday Mechanic early 80's), Los Angeles Times, New York Times, and lots more.
Education/Credentials More than I care to remember.
Basically Franklin Technical Institute in Boston, Northeastern University, Fitchburg State Teachers College, Tufts University, and a lot of factory schools along the way.
Awards and Honors Moto Award winner. And much more.