01 3.4L Impala hesitation/accel problems - Chevrolet Forum - Chevy Enthusiasts Forums

01 3.4L Impala hesitation/accel problems


  Reply  
  #1  
Old  July 20th, 2011, 3:13 PM
  • CF Beginner
    Join Date: Jul 2011
    Posts: 5
    Colorado
01 3.4L Impala hesitation/accel problems

Hi all! Tried searching but didn't find any good answers (probably input the keywords wrong...sorry!).

2001 Impala 3.4L w/145k miles.

Started hesitating and 'laboring' on acceleration, especially when starting from a stop - 30mph. Then again about 50-60 mph.

Motor runs fine through low-high RPMs when in park.

Trans appears to shift just fine, like it always did. Haven't yet checked engine code at O'Reilly but will do so this week.

Thought it might be plugs/wires as they had never been done as far as I know. Plugs wires now replaced, problem still exists.

Search did point to a few candidates (air sensor, etc.) and hopefully there's a code to help me. Check Engine light does not come on. Hoping it's a DIY or low cost fix of course. Any other possible easy suggestions requested.

Thanks!

  #2  
Old  July 20th, 2011, 4:00 PM
  • CF Active Member
    Join Date: Oct 2008
    Posts: 162
    New Johnsonville, TN
You really need to replace the plugs. I'll bet the gap on those suckers is .080 or better by now. You could also have a catalytic converter that's starting to clog up.

  #3  
Old  July 20th, 2011, 4:40 PM
  • CF Beginner
    Join Date: Jul 2011
    Posts: 5
    Colorado
Thanks. I did change plugs/wires myself (front side on Saturday)...gave up on the back ones and had the shop do it yesterday. Picked it up this morning.

  #4  
Old  August 1st, 2011, 7:42 AM
  • CF Beginner
    Join Date: Aug 2011
    Posts: 2
Same problem

I've had this same problem with mine. We've replaced the plugs, wires, and it's had an oil change, etc. It still has a lot of trouble accel.

  #5  
Old  August 2nd, 2011, 12:00 PM
  • CF Beginner
    Join Date: Jul 2011
    Posts: 5
    Colorado
update

Okay. Replaced plugs/wires with no change. Still no check engine light either.

Next candidate was the fuel filter. It was orginal as far as I know, maint guide says it should be replaced every 60k miles or so. So replaced that fairly easily...no change.

Began to think I was victim of the known Catalytic Converter plugged up issue, but of course I am 6 months past the 10 yr limit and 45k over the 120k mileage limit.

It did finally throw a check engine code (PO404), was expecting PO420. PO404 appears to be the EGR (stuck open apparently). So, will buy me some carb cleaner and have a go first at cleaning the EGR.

How to Change the EGR Valve on a Chevy Impala | eHow.com

If that fixes it, I'll take back the Cat I just bought for a refund at O'Rielly. If that doesn't fix it I'll report back with an update.....

  #6  
Old  August 3rd, 2011, 8:59 AM
  • CF Beginner
    Join Date: Aug 2011
    Posts: 2
jbs80106 
Okay. Replaced plugs/wires with no change. Still no check engine light either.

Next candidate was the fuel filter. It was orginal as far as I know, maint guide says it should be replaced every 60k miles or so. So replaced that fairly easily...no change.

Began to think I was victim of the known Catalytic Converter plugged up issue, but of course I am 6 months past the 10 yr limit and 45k over the 120k mileage limit.

It did finally throw a check engine code (PO404), was expecting PO420. PO404 appears to be the EGR (stuck open apparently). So, will buy me some carb cleaner and have a go first at cleaning the EGR.

How to Change the EGR Valve on a Chevy Impala | eHow.com

If that fixes it, I'll take back the Cat I just bought for a refund at O'Rielly. If that doesn't fix it I'll report back with an update.....
Ok, we've already replaced the EGR on my car. Didn't help and now the Engine light is back on. I talked to a mechanic yesterday and was told it could be the Catalyst Converter. Plan to bite the bullet and pay for the diagnostic.

  #7  
Old  August 4th, 2011, 3:36 PM
  • CF Beginner
    Join Date: Jul 2011
    Posts: 5
    Colorado
So, will do a search on this, but in the process of removing my EGR valve I disconnected the air-intake side of the breather tube only to later noticing the other end was disconnected too.

Not sure where it attaches, hopefully it will be obvious but if anyone can point me what to look near that would be great!

Thanks!

  #8  
Old  August 10th, 2011, 4:40 PM
  • CF Beginner
    Join Date: Jul 2011
    Posts: 5
    Colorado
*update*

After attempting to clean the ERG valve with no change. TOok it too local shop. "Think" it's the cat converter that they'll swap for me for $490.

Part plus gasket that I already bought were $198.00.

Youtube vids make it look pretty straight forward. I need to call back to a 2nd shop who I think initially quoted me $325.00. Reputable shop that co-workers trust.

I have access to fully stock auto shop with lifts, tools and on site master mechanics who are there to give advice on base.

So, what to do. $500 sounds high. I was leaning towards paying the $375 to have someone who knows what they're doing just do it. Otherwise I am sure in a day I can DIY for $20 for use of the shop.

Thoughts? Opinions?

Thanks!


Last edited by jbs80106; August 10th, 2011 at 4:55 PM.

  Reply
Tags
Search this Thread
Sponsors