evaporative fuel system leak

Asked by Apr 02, 2013 at 05:00 PM about the 1998 Pontiac Grand Prix 2 Dr GT Coupe

Question type: Maintenance & Repair

My 1998 grand prix GTP is throwing a code for evaporative fuel system leak. I have replaced the gas cap
and the code went away for a while and came back. What else could be causing this condition?

5 Answers


A code P0442 most likely means one or more of the following has happened: - A loose or improperly affixed gas cap - A non-conforming gas cap (i.e. not factory/original brand) - A small leak/hole in a fuel vapor hose/tube - Other small leak in EVAP system - Faulty vent o-ring seal

5 out of 5 people think this is helpful.

I have the same problem...I have had my car in and they "smoked it"...found no leak...they have done this twice...I have replaced my gas cap twice....I leave and the light is off---next time I turn on my car the light comes back on and it says "check gas cap"...how can I find the leak? this is getting very costly and don't have the problem solved yet...

22 out of 22 people think this is helpful.

Mine is a pontiac Grand Prix 06 supercharge. An I'm having same problems. Last week I had to replace my something intake on my engine oil was coming out my engine where it wasn't sapose too. And my engine light came on and now it's back on but this time on my screen it pops up "check gas cap" and the mechanic said it's my evap system.

10 out of 10 people think this is helpful.

yes, I figured out that it is the evap system and the canister rusts out...many people could not figure it out, but I went to a car dealer and the service guy had the same problem in his car ...checked mine and it was....I paid and haven't had any trouble since...and now I even get better gas mileage...amazing!

11 out of 11 people think this is helpful.

I took my car to a smog check shop and they ran it through there computer and it said I ha a EVAC systems leak detected (large leak) I had a brand new fuel pump put in and the guy who put it in forgot to put on the rubber seal the goes around the fuel tank and the fuel pump. When I road around the block know problem. But when I road it about 20 miles. The light turn on. I told the smog shop owner what he did and doesn't think that the problem. Any answer from anybody.

2 out of 2 people think this is helpful.

Your Answer

Add photo

Related Questions

  • leaking under car 2 answers

    when i crack car up it starts to leak from underneath it

    1985 Pontiac Grand Prix


    Maintenance & Repair

  • What is causing the freon leak in my 2006 Pontiac Grand Prix 6 answers

    It continues to leak freon. It lasts only 4-5 days. They have replaced the condensor which was leaking and the o-rings. Checked the hoses and can't find the leak. Any ideas?

    2006 Pontiac Grand Prix Base


    Maintenance & Repair

  • Fuel Injector Misfire 0304 error 2006 Pontiac Grand Prix, 3.8L, base 1 answer

    2006 Pontiac Grand Prix, 3.8L, base Cylinder 4 misfire at startup and under hill climb load Completed - new plugs/wires, new ignition coils, cleaned injectors, then replaced #4 injector. I also have a...

    2006 Pontiac Grand Prix Base


    Maintenance & Repair

  • 99 Pontiac Grand Prix Problems 2 answers

    My red Prix has 223K on it and I really want to get it to 300. For a while I've been driving with little acceleration and no matter how it drives, it always revs to 2500rpms as it shifts to 2nd gear...

    1999 Pontiac Grand Prix 4 Dr GT Sedan


    Maintenance & Repair

  • I have a pontiac torrent, engine light. 1 answer

    My engine light has come on since I bought the car 4 years ago. The mechanic has said it is the emission light, no big deal, nothing wrong. Now I am a customer of Allstate and use their drivewise ...

    2006 Pontiac Torrent FWD


    Maintenance & Repair

Grand Prix

Looking for a Used Grand Prix in your area?

CarGurus has 2,919 nationwide Grand Prix listings starting at $1,995.


Search Pontiac Grand Prix Questions

Pontiac Grand Prix Experts

#1 Js08016
Reputation 4,120
#2 Tom Demyan
Tom Demyan
Reputation 2,770
#3 munron
Reputation 2,150
View All

Related Models For Sale

Used Pontiac Bonneville
542 listings starting at $3,699
Used Chevrolet Monte Carlo
17 Great Deals out of 1,380 listings starting at $1,995
Used Pontiac Grand Am
1,254 listings starting at $1,593
Used Ford Mustang
389 Great Deals out of 47,511 listings starting at $1,800
Used Chevrolet Malibu
860 Great Deals out of 81,222 listings starting at $995
Used Chevrolet Camaro
148 Great Deals out of 32,614 listings starting at $1,729
Used Pontiac Firebird
6 Great Deals out of 745 listings starting at $2,500
Used Honda Accord
767 Great Deals out of 88,117 listings starting at $1,150

Used Cars For Sale

2008 Pontiac Grand Prix For Sale
13 Great Deals out of 437 listings starting at $1,995
2007 Pontiac Grand Prix For Sale
410 listings starting at $2,999
2006 Pontiac Grand Prix For Sale
459 listings starting at $3,500
2005 Pontiac Grand Prix For Sale
376 listings starting at $3,991