Well guys I have an 03 Protege 5 with the famous P0421 code. I replaces both O2 sensors and the code comes back on.
I'm on a bit of trouble since a new warm up cat costs 1200.00 at the dealer.
Does anyone know where to find a aftermarket California legal warm up cat for a reosanable price?
Please let me know.
I had the random missfire trouble before and I found out that my crank sensor bolt was missing I guess the dealer never put it back after my timing belt service.
Hope this will help. Also I use Bosh Platnum 4's and have great results, I'm getting over 475 miles with a tank of gas. Mobil 1 10/30 with mobil 1 oil filter and an engine flush every oil change. My engine looks brand new inside.

 

I've seen countless claims of gizmo plugs like the Platinum 4s delivering increased mileage, however, I've never seen any scientific evidence to back that up; not even a shred.

I submit that if you had used any version of Mobil 1 (I'd recommend losing the 10W-30 in favor of 0W-30) and not bothered with the engine flush, your engine would look just as clean inside. FWIW, I recently pulled the heads off of an engine with about 195,000 miles on it due to a coolant leak. Said engine had been fed a steady diet of Mobil 1 every 10,000 miles or so since the first oil change back in 1998, and it was as clean inside as it was the day it left the factory. That and the frigging honing marks were still on the cylinder walls. I was impressed.

 

Well not making any claims about the plugs just sharing what I use. So if you want to do a test you are welcome to drive my car.
Also the engine flush helps and my MX3 looks a lot better inside since I started using it.
So Mobil 1 and engine flush in my experience and opinion are the best combo for the health of MY engines.
My Mazda 6, protege 5, MX3 and RX8 seem to like it and it's also used by some teams in the formula Mazda series (a car I helped developed and test for Mazda) so please try not to lecture people and maybe share you experince in diferent maner next time.

 

The thing about your experience is that you have no idea how clean your engine would be without using the engine flush; my bet is that the engine flush makes little if any difference in internal cleanliness while at the same time causes small amounts of damage to your engine due to the oil dilution it causes. In otherwords, unless an engine is on life support, an engine flush does more harm than good.

 

I would sugest you do your homework on how those things work, since the metal has been impregnated with the syntetic oil no harmful (damage) as you call it will occur. And since you don't drive the engine just idle it for 5 min no damage occurs.
I have done compresion tests and the engine seems to have almost stck compression.
Since you don't like engine flushes don't use it but stop talking smack about it!

 

Sorry dude, engine flushes are a waste of money and don't do squat for the internal cleanliness of the engine. Your compression tests are irrelevant as properly maintained engine should maintain stock compression for at least a couple of hundred thousand miles.

 

i got a 2003 mazda protege 5 and when im driving and stop at a stop sign or something it sputters like gonna die then when i get it above 2000 rpm it seemsfine but the engine light on i ran a scanner and it said cylinder 4 miss fire and random missfire. and it only does it after it warms up.

 

Luke, please start your own thread, don't jump on the back of another thread.

But first find your solution in here: I know yours is a 2000, so what.

https://www.mazdaforum.com/forum/maz...ght=unofficial