engine with a "miss"

animal

Original poster
Member
Dec 4, 2011
991
2005 TB I6. Has developed a "miss". At speed it is not a problem. When bogging down up a hill it will "miss" a couple of times. It will also do it at a stop light. The miss is a sudden drop of 100 to 200 rpm. It might do it 1 time or 3 or 4 times. Then sometimes it does not do it. I have cleaned the TB and have no codes showing or stored. Have run 5 or 6 tanks of gas thru and my wife gets her gas at the same place so not an issue with the gas .99000 miles and I plan to change spark plugs this weekend. Any other ideas while I am in there?
 

RayVoy

Member
Nov 20, 2011
939
If you have 99,000 miles and the plugs are original, there's your problem..............


A lot of things should be changed at 100k miles, check your owners manual.

filters,
front/rear diffs fluids,
transfer case fluid (for those with 4x4),
transmission fluid,
Maybe the engine oil,
front O2 sensor,
a lot of parts should have a wipe of grease,

This is just a scratch, the list is a lot longer
 

animal

Original poster
Member
Dec 4, 2011
991
RayVoy said:
If you have 99,000 miles and the plugs are original, there's your problem..............


A lot of things should be changed at 100k miles, check your owners manual.

filters,
front/rear diffs fluids,
transfer case fluid (for those with 4x4),
transmission fluid,
Maybe the engine oil,
front O2 sensor,
a lot of parts should have a wipe of grease,

This is just a scratch, the list is a lot longer

Thanks Ray!
I'll add the froht O2 sensor to the weekend project list. All other fluids have been changed.
 

RayVoy

Member
Nov 20, 2011
939
I like changing the O2 sensor when I do the plugs (they get lazy with age), then you know the air/fuel mix should be perfect
 

TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,053
Brighton, CO
Have you cleaned your throttle body? Pretty much a 30-50k mile requirement for the 4.2 engines.
 

animal

Original poster
Member
Dec 4, 2011
991
Yep. First thing I did when this started. I will be changing the plugs and O2 sensor Saturday and see it the problem goes away.
 

RayVoy

Member
Nov 20, 2011
939
When you change the plugs, hold on to them and keep track of the cylinder that each came from.

When the miss is gone, it may be interesting to look at each plug and try to figure out which one was causing the problem.
 

animal

Original poster
Member
Dec 4, 2011
991
Not a bad idea Ray. Thanks
 

harmless

Member
Nov 21, 2011
2,049
RayVoy said:
When you change the plugs, hold on to them and keep track of the cylinder that each came from.

When the miss is gone, it may be interesting to look at each plug and try to figure out which one was causing the problem.

:iagree:

Then feed us some pics of them plugs so we can see too!
 

animal

Original poster
Member
Dec 4, 2011
991
harmless said:
:iagree:

Then feed us some pics of them plugs so we can see too!

Will do buddy!
 

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