cel on after long trip

[smurfxlt]

i have a 99 xlt v8 with 93xxx miles on it. on friday night i drove down the shore, which is about 110 miles, i went about 60-80 the whole way and didnt have any problems, parked my car and didnt touch it until sunday morning when i drove back home with no problems again, but this time i did 75-100 the whole way (i beat my friend in his g35, and he had a 15 minute headstart). a few hours after i got home i went to walmart and im on the highway doing like 60 when the check engine light came on. it was still on when i left walmart, and it was on about an hour and a half later when i left my friends house. it seems to drive fine, does anyone know what it could be? btw i just replaced my water pump the other day...

 

[BrooklynBay]

You have to pull the codes to see what is causing the check engine light.

 

[smurfxlt]

i know, im going to do it tomorrow. i just wanted to know what it might be. and should i drive it or not?

 

[smurfxlt]

just got back from the shop. he told me it was an emissions leak (large). my guess is its the gas cap because i failed inspection for that, then i bought one from my friend and passed. so im guessing the one i bought just broke because it was off his old first gen i think.

 

[Tbars4]

...What was the exact code???

...It could be as simple as a bad or loose gas cap but with out the code your just throwing money at it till you find the right items...

 

[alohamonte]

Most likely a problem with your EVAP system. EGR leak and the like.

 

[smurfxlt]

i dont know what the code is, i asked and he said i didnt need to know and not to worry about it. i didnt feel like explaining the computer age to him so i just said ok. then i went to my job and tried to read it with our scanner but they said i couldnt do it because my mechanic turned the light off and it wont read anything without the light on. so im going to wait till it comes back on and get the actual code. what does it mean if it doesnt come back on

 

[BrooklynBay]

It will come back only if the problem still exists.

 

[smurfxlt]

alright well it hasnt come back on yet. but if it does im going to read the code with the scanner at my job and tell you guys. how accurate of a diagnosis can you guys give me with the code?

 

[BrooklynBay]

It depends upon the code.