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

3 out of 3 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...

21 out of 21 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.

9 out of 9 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 smell, losing fuel, car dies going down rd with no warning, will start back up then acts as if running out of fuel regardless of amount of fuel... 2 answers

    Will O2 Sensor cause fuel smell, bad gas mileage, car not to take fuel at gas pump...major fuel issues please help

    2005 Pontiac Grand Prix Base


    Maintenance & Repair

  • Antifreeze leak 3 answers

    So I changed my water pump in my 1989 Pontiac grand Prix because I thought it had went bad but after I got it changed there's still a leak somewhere and I can't see where its leaking from or anyt...

    1989 Pontiac Grand Prix SE


    Maintenance & Repair

  • fuel problem 1 answer

    2003 Aztec turn key on, fuel pump comes on fuel pump primes system engine starts runs until it runs out of fuel fuel pump does not come on after initial prime, turn key off and back on system primes ...

    2003 Pontiac Aztek


    Maintenance & Repair

Grand Prix

Looking for a Used Grand Prix in your area?

CarGurus has 3,705 nationwide Grand Prix listings starting at $879.


Search Pontiac Grand Prix Questions

UK Questions

Are you a UK consumer? CarGurus now has a discussion forum in the UK.

Pontiac Grand Prix Experts

#1 Js08016
Reputation 3,890
#2 Tom Demyan
Tom Demyan
Reputation 2,580
#3 munron
Reputation 2,060
View All

Related Models For Sale

Used Pontiac Bonneville
9 Great Deals out of 649 listings starting at $1,375
Used Chevrolet Monte Carlo
21 Great Deals out of 1,689 listings starting at $2,491
Used Pontiac Grand Am
1,656 listings starting at $1,298
Used Chevrolet Malibu
1,107 Great Deals out of 82,566 listings starting at $2,328
Used Chevrolet Camaro
378 Great Deals out of 40,505 listings starting at $3,500
Used Ford Mustang
537 Great Deals out of 42,626 listings starting at $1,699
Used Buick Regal
151 Great Deals out of 11,581 listings starting at $1,850
Used Jeep Grand Cherokee
898 Great Deals out of 66,108 listings starting at $1,500
Used Nissan Maxima
365 Great Deals out of 24,281 listings starting at $999
Used Nissan Altima
1,060 Great Deals out of 82,197 listings starting at $1,988

Used Cars For Sale

2008 Pontiac Grand Prix For Sale
17 Great Deals out of 472 listings starting at $900
2007 Pontiac Grand Prix For Sale
515 listings starting at $2,995
2006 Pontiac Grand Prix For Sale
3 Great Deals out of 632 listings starting at $2,000
2005 Pontiac Grand Prix For Sale
436 listings starting at $5,900