Pontiac Repair: 95 Grand Am 4 Cyl DOHC 120K+ miles, resistance range, exhaust fumes

Question
Car sputters - Will not go any faster than 25 or 30 MPH - Definately will not go up a hill. No smoke anywhere, but strong exhaust fumes. Oil just changed with no signs of water in it - I have changed oil, oil & air filters, the spark plugs and the fuel filter - Someone suggested ignition coil housing was bad. How can I check it to know if it's bad before I buy the part? What's the ohm's resistance range to look for? Car was running grea one minute, then starts acting up the next. Any help is appreciated.

Answer
Hey Tony:
I second the coil housing assembly it's something inside that cover assembly either that the ignition module or a bad coil. On that engine the coils are paired up cylinders 1/4 ans 2/3 share the same coils. if you take that apart the coils shouls have about 6-8K ohms across the secondary side and and approx. 1 ohm across the primary side. The secondary side is the plart that fire the plugs off. to check for sprak on this engine is a pain you need test wires and a spark checker. the cover it's self you can check for resiatnace between the tips where the plug boots go on with all the coils out of the cover you should not have an resiatnce between any of the tips if you do that's your problem. The problem is the insulation breaks down in that cover and the spark can jump the gap even if they do not show shorted together the spark can cross fire inside that cover. A lot of the time it's just a guess that pans out. I hate "guessing" as well but some times you have to. Good luck :)