Struggling Upon Acceleration
Thread Starter
Joined: Jun 2009
Posts: 1,281
Likes: 1
From: San Antonio, Tx
Went to vatozone to pick up a can of Seafoam but before I even got there I noticed the car was acting up again.
Well, actually, I ran a couple of errands before heading to autozone. The whole time the car ran fine, no problems at all.
After making a stop, and then turning the car back on to head to autozone the car starts to bog in 1st and 3rd gear.
Here's the symptoms/issues I'm experiencing:
At a stop/idling (it seems only after the car has reached operating temp) - car seems to "pop?" or "bump". Similar to the feeling of sitting next to someone with a loud sub blasting. You can feel the vibration pulse through you.
So car pulsates randomly.
Starting in 1st - Car seems to not want to go, step on the gas and it moves but hesitates and struggles, then suddenly catches and goes.
2nd- no problems at all it seems.
3rd- similar to first gear. If I really ease into gear it's fine, but if I need to downshift and go hard, it struggles, and jerks, then randomly catches and goes.
4th- no issues.
5th/Reverse- never got into 5th and no problems in reverse.
So I make it to Autozone and have them check out the SES light.
Same problem as before I believe. Here's what the printout they gave me said.
Troubleshooting P0420
Domestic
Definition
Catalyst efficiency low-bank 1
Explanation
The oxygen sensors monitor the Catalytic Converters ability to store oxygen.
Probable cause
- Catalytic converter defective (failure possibly due to #2, 3, or 4)
- Engine misfire or running condition
- large vacuum leak
- Engine oil leakage into exhaust-valve guide seals, piston rings.
Any help would be greatly appreciated.
Well, actually, I ran a couple of errands before heading to autozone. The whole time the car ran fine, no problems at all.
After making a stop, and then turning the car back on to head to autozone the car starts to bog in 1st and 3rd gear.
Here's the symptoms/issues I'm experiencing:
At a stop/idling (it seems only after the car has reached operating temp) - car seems to "pop?" or "bump". Similar to the feeling of sitting next to someone with a loud sub blasting. You can feel the vibration pulse through you.
So car pulsates randomly.
Starting in 1st - Car seems to not want to go, step on the gas and it moves but hesitates and struggles, then suddenly catches and goes.
2nd- no problems at all it seems.
3rd- similar to first gear. If I really ease into gear it's fine, but if I need to downshift and go hard, it struggles, and jerks, then randomly catches and goes.
4th- no issues.
5th/Reverse- never got into 5th and no problems in reverse.
So I make it to Autozone and have them check out the SES light.
Same problem as before I believe. Here's what the printout they gave me said.
Troubleshooting P0420
Domestic
Definition
Catalyst efficiency low-bank 1
Explanation
The oxygen sensors monitor the Catalytic Converters ability to store oxygen.
Probable cause
- Catalytic converter defective (failure possibly due to #2, 3, or 4)
- Engine misfire or running condition
- large vacuum leak
- Engine oil leakage into exhaust-valve guide seals, piston rings.
Any help would be greatly appreciated.
Thread Starter
Joined: Jun 2009
Posts: 1,281
Likes: 1
From: San Antonio, Tx
Coil packs are like $26/ea at autozone, and the PCV valve is like $3 so that's something I can do here soon.
The wires are brand new MSD wires (the red ones) that were just recently installed.
I do not have a cat on the car.
I'm a little confused, isn't the P0420 code a problem with the o2 sensor post-cat? So naturally, having no cat, I should throw that code, right?
But the way the car is struggling is the way it ran when the 2 sensors before the cat were bad. So what the heck?
Staging Lane
Joined: Dec 2007
Posts: 91
Likes: 0
From: New Albany, Ohio
Ive seen the coils go bad on the 3800. The car throws the P0420 code because you need to get it tuned out. The ECM calculates how the engine the engine is running by your two front O2 is reading. Then it calculates how the cats are suppose to work by the rear O2. Since you have no cats the ECM thinks the cats are bad due to no change in voltage from the rear O2. O2 sensors will not cause a miss. I would bet the coils but wouldnt rule out a sticking egr valve.
Last edited by chevy8806; Feb 8, 2010 at 06:58 PM.
Thread Starter
Joined: Jun 2009
Posts: 1,281
Likes: 1
From: San Antonio, Tx
Ive seen the coils go bad on the 3800. The car throws the P0420 code because you need to get it tuned out. The ECM calculates how the engine the engine is running by your two front O2 is reading. Then it calculates how the cats are suppose to work by the rear O2. Since you have no cats the ECM thinks the cats are bad due to no change in voltage from the rear O2. O2 sensors will not cause a miss. I would bet the coils but wouldnt rule out a sticking egr valve.
The egr valve? This is a new suggestion. Any more info on this?
What are your thoughts on the PCV valve? It's a $3 part and like a 2 minute swap, but would it cause issues?
TECH Enthusiast
Joined: Apr 2009
Posts: 531
Likes: 0
From: Pocatello Idaho
I would just do all 3. Really easy and cheap. When I had one go bad it was because moisture caused it to bulge, but I only saw it from the bottom. Looked a lot like lime build-up. Same symptoms that you are having and it was a coil. Just replaced all 3.
Thread Starter
Joined: Jun 2009
Posts: 1,281
Likes: 1
From: San Antonio, Tx
I think I'm going to have to drive the car in it's wack condition to work tomorrow and hold off until doing any replacing of parts until Thursday. 
Since the PCV is so cheap, I'm going to go ahead and replace that, and the coil packs are like $25/ea so that's not too terrible. This car likes to nickel and dime me!
Since the PCV is so cheap, I'm going to go ahead and replace that, and the coil packs are like $25/ea so that's not too terrible. This car likes to nickel and dime me!
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Verdad Gallardo Thread Starter
Joined: Jun 2009
Posts: 1,281
Likes: 1
From: San Antonio, Tx
I checked the PCV valve, and it was black and gunked up with idk what. I cleaned it off a little with a napkin and replaced it. Drove to AZ to get a replacement, and drove to work. Car ran fine until I got to the parking lot and it started running like ****.
I replaced the PCV valve with the new one and put in a new air filter.
After work, I turn on the car and it's idling rough. The drive home was scary, car did NOT want to move. Worse than before.
I managed to crawl to autozone and picked up 2 (they only had 2) of the 3 coilpacks. I guess I'll be doing these tomorrow.
Any other advice guys?
I replaced the PCV valve with the new one and put in a new air filter.
After work, I turn on the car and it's idling rough. The drive home was scary, car did NOT want to move. Worse than before.
I managed to crawl to autozone and picked up 2 (they only had 2) of the 3 coilpacks. I guess I'll be doing these tomorrow.
Any other advice guys?
Thread Starter
Joined: Jun 2009
Posts: 1,281
Likes: 1
From: San Antonio, Tx
Old coil packs are out. New ones in tomorrow.
Had a hell of a time getting to the screws tucked under the cowl.
Took 3 trips to vatozone and $$ to buy a flexible extension and a 2" skinny extension to get to them. Install should be easy... hopefully.
Had a hell of a time getting to the screws tucked under the cowl.
Took 3 trips to vatozone and $$ to buy a flexible extension and a 2" skinny extension to get to them. Install should be easy... hopefully.
Sounds like a coil to me , sadly there isnt really an easy way to check the coils. What i have done in the ast is get a spark tool which has a light in it and put it in line with the plug if it lights up you have spark. Other wise jus take the plug boot off and listen for a click.... However wear rubber gloves and be careful!
Thread Starter
Joined: Jun 2009
Posts: 1,281
Likes: 1
From: San Antonio, Tx
^Thanks, I'm hoping at this point it is just a bad coil.
I did notice that one pack (the middle one-of course) had ALOT of orange, what I'm guessing was like oxidation, rust, or some kind of corrosion, on one of the terminals. I hope that's the culprit. The other 5 prongs seemed to be pretty clean.
Will post update later.
Any thing I need to do/worry about?
Put coils in, install correct wires to each terminal, and replace neg battery terminal, and start her up, yes?
I did notice that one pack (the middle one-of course) had ALOT of orange, what I'm guessing was like oxidation, rust, or some kind of corrosion, on one of the terminals. I hope that's the culprit. The other 5 prongs seemed to be pretty clean.
Will post update later.
Any thing I need to do/worry about?
Put coils in, install correct wires to each terminal, and replace neg battery terminal, and start her up, yes?
Thread Starter
Joined: Jun 2009
Posts: 1,281
Likes: 1
From: San Antonio, Tx
Update-
Replaced coils this afternoon and let the car idle for a few minutes. No issues there, so I took the car for a spirited drive around the surrounding streets around campus. Experimented with accelerating fast/hard, and slow/babying it. Perfect response regardless, and no problems at all.
Finger's crossed, this was the problem and it's now resolved!
Time will tell.
Thanks to everyone that posted for all the help!
Replaced coils this afternoon and let the car idle for a few minutes. No issues there, so I took the car for a spirited drive around the surrounding streets around campus. Experimented with accelerating fast/hard, and slow/babying it. Perfect response regardless, and no problems at all.
Finger's crossed, this was the problem and it's now resolved!
Time will tell.
Thanks to everyone that posted for all the help!
TECH Apprentice
Joined: Jan 2010
Posts: 333
Likes: 0
From: Tucson, AZ
Thread Starter
Joined: Jun 2009
Posts: 1,281
Likes: 1
From: San Antonio, Tx
Staging Lane
Joined: Dec 2007
Posts: 91
Likes: 0
From: New Albany, Ohio
The only way i was taught to test for bad coils if you or anyone comes across it again, it to use a test light and make a very tiny poke in the boot of the wires on the coils. Hook the test light to ground. while the car is acting up, probe the top of the boot of the wire. Which ever one that doesnt cause the engine to change the way its running then assume the coil is bad.
The only way i was taught to test for bad coils if you or anyone comes across it again, it to use a test light and make a very tiny poke in the boot of the wires on the coils. Hook the test light to ground. while the car is acting up, probe the top of the boot of the wire. Which ever one that doesnt cause the engine to change the way its running then assume the coil is bad.
