I have a 1999 Dodge Neon R/T 70,000 miles. 2.0 L DOHC . The other day I went to replace the spark plugs. The guy at the auto parts store recomended platinum plugs. My car did not already have platinum plugs but he said that was fine. The plugs were pre-gapped. After I changed the plugs I drove the car about 25-30 miles and it started to miss. I called the auto parts store and they said that the plugs were pre-gapped at .045 but should be gapped at .050 so I re gapped them. I then drove about 15 miles and the missing started to get worse. I called a different place and was told that my car should have been gapped at .035. This time when I re gapped them there was a white sticky residue on the plugs that kinda smelled like candy. My car hardly made it home that night. I took out the new plugs and put in the old ones. The car runs perfect until the engine gets hot (it does not overheat and never has) Once the engine gets hot it loses all power. When I put my foot on the gas it seems like it wants to stall out and will if I keep my foot on the pedal. If I take it off it idles rough. I did a OBD II test on it and got the code p1492 which I was told was apl solenoid circuit malfuction or the purge solenoid. Could this cause the car to act this way. What other things could it be? I have money to get a diagnostic test on it but then won't have the money to fix it. Any suggestions would be helpfull. If it makes a difference it is a 5 speed and I also changed the spark plug wires.