Pontiac Repair: 92 Grand Am idles rough, knock sensor, fuel economy

Question
QUESTION: Hi Todd,

 I have a 92 Grand Am Quad4 SOHC VIN 3, last friday morning, i went to start it and it was idling really rough, went to drive off, and had considerably less acceleration and power.  Also is sucking up gas like a sponge...1/4 tank to go about 60 miles...=(  
What could be the trouble?

         Thanks!


ANSWER: Hi Earnie:

My guess is the car is only running on 2 or 3 of the 4 cyliners. thus the ones that are running the engine are working harder thus the decreased fuel economy. It could be a bad coil or ignition module. It could have a injector problem or even an engine mechanical issue where it's low on compression. Without seeing the car it's hard to say. Has any service engine light come on? That would be a place to start. Good luck :}


---------- FOLLOW-UP ----------

QUESTION: Hi, Todd...
 Me again...about the coil and ignition module...i figured that could be it...but im having no luck in finding these components...can you tell me where they are located?

         P.S.   i have had a check engine light come on, but the code was for a Detonation/Knock Sensor...thats been coming on since i got the car over a year ago, tho...dont know where that one is either...=/


Answer
The coils and ignition module are mounted to the uderside of the big cover on top of the engine. The Knock sensor is attached to the block I has a signle dark blue wire on it. A knock sensor unless it's gone horribly wrong would not affect the way the car runs. And even if it were to have gon horrible wrong in terms of the signal it produces if the computer see's it is not working correctly it will ignore that input untill the fault has been repaired.
Once again good luck :}