I am experiencing a 430 engine miss. Vehicle has 70 K miles and miss began at about 60 K. It occurs with light throttle input w/wo cruise control on slight inclines. Will also occur from a stop on level ground. Serviced every 5 K at dealership since new. Stock except for K&N air filter. Had induction service with no change in engine miss. Any ideas out there?

 

Throw out the piece of crap K&N filter.

Buy a can of CRC MAF cleaner at autozone, remove your MAF, and clean the hot wire within the MAF with CRC cleaner. Or better yet, just replace the MAF, its only $120-150, depending which dealer you go to.

What happens is, your MAF, which is immediately after the filter in the intake piping, has a hot wire that is heated to 400 degrees, and the oil from the K&N filter bakes onto it, and all the tiny dust/dirt particles that get through the filter stick to that oil, and your MAF no longer reports the correct air quantity to the computer, and the computer in turn sends the wrong amount of fuel to the engine, and thats why you're having a miss.

I had exact the same problem with my GS430. I don't know how that crooked K&N company still hasn't been sued off the face of the earth.

 

^
nope that is due to POOR USER re-oiling. i've had mine on since i bought the car and since then i have put on 20k miles and guess what? no problems with my MAF. ive also cleaned it 3 times already, done properly.

back on topic though,

Habu4, it does sound like something ignition related, spark plugs or spark plug wires fouled up could cause this. are u mechanically inclined to be able to remove the spark plug wires?

 

Wrong, when I had it on my GS, I never re-oiled it, I only had it on the car for about six months, and the miss started. When I removed the MAF, the hotwire had a good chunk of dirt on it, the resembled ear wax. Cleaned it with CRC MAF cleaner, and the problem was gone.

Which car do you have your K&N on? If its on your LS, then it wont cause problems, early LS does not use a hotwire MAF.

 

check the PSI on the fuel pump. First signs of a failing fuel pump.

 

The K&N filter has been installed on my 2003 SC430 for about 20K miles. Would not ignition problems be more inclined to to cause an engine miss thoughout the power range? Dealer can duplicate the problem but not find the cause.

 

usually its over oiling which causes issues with the MAF, imo I would just stick with a paper filter, Wix/Napa Gold are great paper filters.

 

Like I said, start with the MAF cleaning. It will cost you $4.00 for the can of cleaner, and if the problem persists, then you have other options.

 

I know on the 96+ Toyotas, the MAF was changed to a wire device, which gets gummed up by the oil from K&N filters. I'd clean the MAF and stick w/ the factory airbox. The only proven difference w/ the K&N vs. OEM is it allows more dust into your engine, meaning accelerated engine wear. You ought to have your oil tested and check the silica levels to verify.

 

Thanks all. Step one: I have changed out the K&N with a OEM filter. I checked the MAF and the "wire" is immaculate. I'll keep you posted.

 

I'm glad I didn't put a K&N filter in my car after reading all of this. I didn't think about how all that oil would would affect things beyond the filtration. Thanks

 

Get rid of that K&N filter.

 

In 98 I bought a brand new Mustang Cobra. installed a K&N almost immediately. At the first service the service manager at the FORD dealership told me that a K&N filter could void the warranty. After laughing in his face I showed him the Ford Speed Parts catalog and asked him what kind of air filter was recommended in the book. Of course it was a K&N and at that point the filter stayed and he never mentioned it again for 10 years that i had the car serviced there.

Back to the thread..the Cobra exhibited the same symptoms the OP has at about 58000 miles. It was the fuel pump.

 

A few months ago before the winter, I pulled the intake off and cleaned my throttle body. It didn't look dirty, but it fixed the problem you are having. Now it's doing this again, so Im going to clean it again and see what happens. It's about that time to take it in for service anyway.

 

Damn, taking my K&N filter out ASAP lol