Would air intake hose not connected influence upper plenum/catlytic converter issues?

Asked by Jul 16, 2013 at 07:50 PM about the 2002 Pontiac Grand Prix GT Coupe

Question type: Maintenance & Repair

Recently had some work done on my 02 Pontiac Grand Prix GT.  After having repairs
done I drove straight home, roughly 5 mins away from shop, and did not use car again till
next morning when I was "going" out of town.  Roughly 10-15 minutes after I hit the
interstate I had to pull over because my service engine light kicked on and was confused
as to why.  When I popped the hood I saw that my air intake hose was not connected to
the box mount where my air filter is located.  I figured that was the issue, grabbed a
screw driver, tightened the O-clamp back up and tried to get her going again.     Car was
able to start and run however, I wasn't able to accelerate well at all.  I ended up getting
the car towed back in to town to avoid any further damage, thinking it was transmission
issues, and took it back to the repair shop where I had the work originally done.  
Explained to them about the neglegence of securing the air intake hose and asked them
to diagnose the problem that I am now having.  After another day of leaving the car in the
shop, I am now looking at having to replace the upper plenum AND the catalytic
converter.  In all, my question consists of:  Would the neglegence of the company not
properly securing the air intake hose have influenced the upper plenum to
melt/overheat/need replacing and also influence the issues I am running into with
replacing the catalytic converter?  I know that some things just happen as a coincidence
to one another but strongly feel that the air intake not being secured properly influenced
this chain reaction.  Any help would be greatly appreciated, also keep in mind I am not
mechanically inclined by any means so my verbage may be a lil off.  Feel free to ask if
you need clarification on anything.  Thanks in advance!!!

4 Answers


I never heard of ever needing a new upper plenum, they are cast. The cats would need to be replaced if they were clogged, and by you driving a short distance without an air hose connected, no way. Something doesn't sound right. I think besides the air intake some other hose wasn't connected properly. A reputable shop would always road test the car before letting the customer drive it off the lot. Drive as fast as you can to another mechanic to resolve your issue!

1 of 1 people found this helpful.

sounds like a misdiagnosed on the plugged cats, and maybe the plenum ,although they are plastic and do crack, unhooked filter tube should not damage a cat, if it ran strong before.Unhooked will throw it in limp mode, or factory presets and light will come on.without tube your not measuring air volume and air temp. Is filter and passages clear for flow Before and after filter, I say before as duct tubes can acquire mice nests and leaves etc. if a moron left the duct off my car after repair I,d say this is not a mechanic , very few are VERY FEW! Get another opinion, what was the first reason for repair shop ?.

1 of 1 people found this helpful.

Thanks Tom, definitely plan on going to a different car shop in the future. In the process of a move so will have to locate a new one once that is all finalized and can actually get my car running again!!! 7jimm7, as far as I could tell car was running great prior to taking it to the shop for original repairs, one thing I may also need to point out is that this car has roughly 107k miles on it now. I had sway bar replaced and some bushings for original repairs, they also checked on the ABS wire harness to see if it was connected properly since the indicator light popped up as well. They "claim" they had no reason to go under the hood for any of these. Sway bar and bushings I could understand, ABS wire harness I would assume would have to be checked either under hood or behind dash. Again, not sure since this is not my cup of tea.. haha... I stay on top of all oil/lube changes and flushings of fluids on a average suggested basis. Hope this helps. Thanks again for input so far!!!

ABS still exists, sent to new location for a second look at the issues. Seems I will be looking into replacing the upper plenum and the catlytic converter after all. Good thing this second shop ran me a couple hundred bucks cheaper. Thanks for the input from both of you!!

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