My 97 GMC pickup has a cylinder 4 misfire code. I have changed the spark plugs and wires, and EGR valve. I have cleaned up the distributor cap and it looks in good shape (no cracks, etc). I did a compression test and had 150 to 180 range over all cylinders. I have checked the #4 spark plug for a spark and it fires every time. I have ohmed out the injectors and they are ok. I inspected the #4 injector tip and it is shiney and gold colored. I have ran 1 liter of Lucus injector cleaner through it over 2 1/2 tanks. The truck also has trouble starting. I can hear the starter engage but won't turn the engine hardly at all. It's like it's compression locked and sometimes when I realise the key it stumbels 1 rotation like a back fire. The exhaust has a rich smell fuel in it and the fuel milage has droped from 12-14 MPG to 8-9 MPG. HELP? I'm out of possabilities that I can think of.
Oct 18, 2008 at 4:34 PM
