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

Asked by Mar 15, 2017 at 05:51 PM about the 2006 Pontiac Grand Prix Base

Question type: Maintenance & Repair

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 0455 error which I'm pretty sure is emission canister valve fail.  I've bought the replacement but have not installed yet. (I've already replaced gas cap and purge valve).  I'm doubting that would impact a single cylinder or the misfire at all.
I'm about to go change the #4 injector connector.  After that I'm thinking I have a manifold gasket leak?  Any diagnostic tips or suggestions are appreciated.  Thanks

2 Answers

87,405

Check the intake manifold bolts to make sure there snugged up. You on the right path for diagnosing the problem. Other causes, I didn't include what you have done already... Fuel injector 4 harness is open or shorted, Fuel injector 4 circuit poor electrical connection, Ignition coil 4 harness is open or shorted, Ignition coil 4 circuit poor electrical connection, Insufficient cylinder 4 compression, Incorrect fuel pressure, Intake air leak...Here is some info on your other code....P0455 PONTIAC - Evaporative Emission Control System Leak Detected Gross Leak...Possible causes; Missing or loose fuel cap, Incorrect fuel filler cap used, Fuel filler cap remains open or fails to close, Foreign matter caught in fuel filler cap, EVAP canister or fuel tank leaks, EVAP system hose leaking, Fuel tank leaking...The P0455 it’s a very common code, because the code is set if the gas cap is loose or missing. Start by tighten the gas cap and clearing the code. In most cases the code can be clear by disconnecting the car battery for about 30 minutes.

for your po 455 code. there is a rubber line, about 1.25" in diameter that runs from the evaporator canister to the fuel tank. about half way along the hose it is cut in two and reconnected with a plastic pipe on the inside, maybe for production reasons, rather than using a continuous hose. you will find this hose by going under the left rear wheel. on my 04 this connection was leaking air. use two jublie clamps to seal the tubes around the pipe. that solved my air leak. good luck

Your Answer:

Grand Prix

Looking for a Used Grand Prix in your area?

CarGurus has 1,675 nationwide Grand Prix listings starting at $1,350.

ZIP:

Pontiac Grand Prix Experts

  • #1
    Js08016
    Reputation
    4,780
  • #2
    munron
    Reputation
    2,950
  • #3
    Dorian Hendricks
    Reputation
    2,390
View All

Related Models For Sale

Used Chevrolet Impala
537 Great Deals out of 25,594 listings starting at $790
Used Dodge Charger
413 Great Deals out of 31,902 listings starting at $1,900
Used Pontiac Bonneville
4 Great Deals out of 306 listings starting at $2,995
Used Chevrolet Monte Carlo
5 Great Deals out of 986 listings starting at $2,244
Used Pontiac GTO
5 Great Deals out of 402 listings starting at $5,450
Used Ford Mustang
378 Great Deals out of 39,450 listings starting at $1,995
Used Pontiac G6
47 Great Deals out of 2,597 listings starting at $1,400
Used Chevrolet Malibu
620 Great Deals out of 53,590 listings starting at $1,300
Used Pontiac Grand Am
729 listings starting at $2,200
Used Chrysler 300
423 Great Deals out of 19,970 listings starting at $1,990
Used Honda Accord
719 Great Deals out of 96,716 listings starting at $1,225

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.