Sputtering weekly

…i have a 1994 gmc yukon. it sputters everytime i drive it. it broke down on the interstate and i took it to my mechanic. my roter cap had to be replaced because it was not spinning and firing appropriately. it ran better for about a day and started sputtering again. at that point i cleaned my k & n air filter and replaced my fuel filter. i also used HEET gas treatment. i’m running out of options…do you have any suggestions?

HOw long have you been using the K&N? Is it a drop-in paper filter or oiled?

You are not running out of options, as potential for problems is really great. I think you need to clarify, as he could have replaced a distributor cap, but a distributor cap does not spin and fire. He could have replaced a rotor because it did not fire, but if a rotor does not spin then the distributor is the problem. If it does not fire it could be because the rotor is bad, but if it still does not fire then probably the coil is bad. Can you clarify the repairs? Can you find a new mechanic?

If an oiled K&N filter, try cleaning the Mass Air Flow sensor with a product formulated to do this. Then replace the K&N filter with a OEM style aftermarket air filter. If this fixes the problem, throw the K&N filter in the garbage.


You’ve not accessed your only real option: diagnosis.

If your “rotor cap” had to be replaced because of misfiring and that helped temporarily, I can only assume that this 15 year old workhorse is in desperate need of long overdue maintenance. When was the last time you had a complete tuneup? You know, wires, plugs, rotor, filters, stuff like that.

Did the mechanic change the rotor too when he changed the cap…I hope? both need to be changed as a set.

As a possible contributor but as possible “aside”, those K&N filters have been known to introduce oil into the intake which can then get burned with the gas and contaminate the oxygen sensor. When the plugs are pulled it’d be a good idea to look at their condition.

That K & N filter could have easily fouled the Mass Air Flow sensor (MAF) of your Yukon.

The regular “paper” type of filter that is available for many different suppliers does a very decent job of filtering out particles, but without the potential problems resulting from a K & N filter with a bit too much oil.

If you have not cleaned or replaced the MAF, give that a try. If that is successful, get rid of the K & N filter, and install a “conventional” air filter.

i have had it for about 2 years now…from what it sounds like…i think i might try the paper filter…the k and n was already installed when i bought it, so i kept using it. i think it’s time for a change.