Are there any vacuum lines on a 2005 Pontiac Grand Prix Base Sedan 4-Door 3.8L 3800CC 231Cu. In. V6 GAS OHV Naturally Aspirated? MY scan tool is showing a P0401 code (Insufficient EGR Flow).

Asked by rtrinca Feb 08, 2019 at 11:51 PM about the 2005 Pontiac Grand Prix Base

Question type: Maintenance & Repair

Are there any vacuum lines on a 2005 Pontiac Grand Prix Base Sedan 4-Door 3.8L 3800CC 231Cu. In. V6 GAS OHV Naturally Aspirated? MY scan tool is showing a P0401 code (Insufficient EGR Flow). I ordered a new MAP sensor and PCV Valve. Could it be anything else? Also now have a P0300 code. And oil in the lower air intake manifold. I cleaned out the oil and carbon buildup. Checked the fuel injectors. Replace plugs and wires. EGR valve and connecting tube. Could a bad intake manifold gasket be the problem? Either upper or lower? Or maybe the MAP sensor just got clogged and shut down the Idle Air Controller, which stalled the engine? Any professional help would be greatly appreciated. The car was running great before this happened and then in a couple of days started showing signs of a misfire. Then bang P0300 random multiple intermittent misfire. What could cause the PCV Valve to get covered in oil? A high crank case pressure buildup? But what caused that? Can a bad MAP cause that? Or anything else?

3 Answers
26,245

taver91 answered 5 years ago

WOW! You need to simplify and go back to basics. To answer your first question, yes, your car has vacuum lines and one is part of the EGR system. Start there and check/replace this line and the one from the PCV and see what effect it has.

Mark helpful

rtrinca answered 3 years ago

I don't see any vacuum lines on my 2005 Pontiac Grand Prix. Everything is electronic. The car does not kick out a code when I drive it on the highway. It only happens when I'm going slower than 45 mph. I can drive several hundred miles on the highway with no P0401 code or any codes at all, but as soon as I slow down and run 35 mph or so for a while the code kicks in. I did have a bad PCV and replaced it. Cleaned up the air intake and all EGR passages, replaced the EGR valve, but I bought a cheaper one (so maybe it operating slightly out of specifications at slower speeds or rpm's). I did not replace the air intake manifold gasket. Could this be the problem or may it be a wiring problem that only occurs on rougher roads? It runs really good when the check engine light is not on and pretty good when it is.

Mark helpful

Your Answer:

Related Questions

Grand Prix

Looking for a Used Grand Prix in your area?

CarGurus has 3 nationwide Grand Prix listings and the tools to find you a great deal.

Postal Code:

Shortcuts

Search Pontiac Grand Prix Questions

CarGurus Experts

  • #1
    munron
    Reputation
    8,140
  • #2
    james sparrow
    Reputation
    7,480
  • #3
    Dorian Hendricks
    Reputation
    6,000
View All

Find great deals from top-rated dealers

Search

Related Models For Sale

Used Pontiac Bonneville
2 listings
Used Pontiac GTO
5 listings
Used Pontiac Grand Am
2 listings
Used Pontiac G6
16 listings starting at $3,995
Used Chevrolet Monte Carlo
5 listings starting at $9,800
Used Chevrolet Impala
5 Great Deals out of 131 listings starting at $3,495
Used Ford Mustang
38 Great Deals out of 1,626 listings starting at $8,995
Used Dodge Charger
33 Great Deals out of 901 listings starting at $5,995
Used Chevrolet Silverado 1500
193 Great Deals out of 7,903 listings starting at $3,000
Used Toyota Camry
50 Great Deals out of 1,123 listings starting at $784
Used Chevrolet Corvette
28 Great Deals out of 765 listings starting at $15,900
Used Honda Accord
47 Great Deals out of 973 listings starting at $2,995

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. Content will be removed if CarGurus becomes aware that it violates our policies.