Hesitation between 3-5000 RPM
 

Alright, I have spent the last 4 hours reading through posts and wanted to make sure I was on the right path....

2 months ago I just purchased an '04 BB 6-speed with 90,000 miles on it. The engine had just been replaced at 84,000 miles by Mazda so I have all new plugs, coils, wires, etc. so I don't think that it is the issue.

Over the last week I have noticed a hesitation (No CEL lights) between 3,000 and 5,000 RPM(ish). It is really strange because after about 4,700 or so it is like a light switch and it just opens up and it just pulls all the way to 9,000+. I only run 92 octane and havent really had any issues with starting ever.

I just bought a K&N Typhoon from a forum member and am waiting for that to be delivered before I clean the MAF sensor which is one of the things I was thinking may be part of the issue. I also make sure i redline it a few times a week with some spirited driving to keep the "carbon" away :rolleyes:.

Anybody have any other ideas or anything? It seems hard to believe that a engine with about 7,000 miles is having issues already.

Check your cat. If that's good, check your fuel pump
Also, the typhoon is not a great choice. Others will agree. It draws in too much engine bay heat...

I heard that If you build a cover for the top and insulate it the Typhoon isn't all that bad, besides I got a really good deal on it so i dont feel bad.

Also I thought if the cat was bad it would throw a CEL?

building a cover will help, But don't be too surprised if it changes your performance in a bad way. Not saying it will!

It would throw a cel, but not always. I was recommending check that as it's the easiest.
You could also check:
Air filter/ MAF sensor
fuel pump
ess
etc etc

Ummm yeah so .... just going to throw this out there to make sure.
You're not trying to do this when the car is cold, are you?

There is a rev limit until the car warms up.

Clean the Maf and Eccentric shaft sensor.
Could be a bad Front O2 sensor or Maf.

Some other things to consider while you are watching the RPMs sweep

VFAD = 5250 rpm
APV = 6250 rpm
SSV = Load base however there is a rpm hold until 3000 rpm on a cold engine -40 to 32 f
VDI = 7250 rpm

Could be a sticky SSV

You should get a cel if the Cat is bad. That would be the Rear O2 sensors job and only job.

LOL
You posted while I was posting ... damn hockey game distracted me :D

At the OP.
What he said ^^^^

Sorry I forgot to mention that, I do of course wait till it is all warmed up before I rev it above 4k lol.

I'm not familiar K&N Typhoon.
I know the series one had problems.

Does the typhoon setup retain the maf screens. Those screens are very important to smooth out the air flow. You should have at least one installed.

(Ooo what's that, I hear TeamRX8 coming right now to tell me otherwise)

I did at least make sure that it was a series 2 Typhoon.

So did this problem start right after you installed the Typhoon?
How long have you had the typhoon installed?

Sorry, I havent gotten the intake yet, it is still all stock. I was saying I was just going to wait on the cleaning the MAF until I got the Typhoon and went to install everything.

Hmm...well on the way home I tried to pinpoint the exact rpm it started at with a slow acceleration throughout the revs. I did not get a hesitation, but instead got a flashing CEL that went away after a few seconds.

Interesting ...
Too bad it didn't stay on.
Maybe it stored it in the ECU?

Any chance you have an Autozone close by?

I am going to run by there once i get done with a group meeting (poor college kid) I just hope they are open when I am done. If not then tomorrow.

I was just thinking that I should go ahead and buy a reader for myself last night lol...this car may make it worth purchasing.

A Cobb AP is priceless for doing troubleshooting

Just for the sake of covering all the easy bases before things get complicated and costly - are you sure that plugs/coils/wires were replaced when the replacement engine was installed? It is not unusual for these parts to get swapped over from the original engine to the replacement. Are you sure that maybe one of the wires/coils is not up to par?

According to the paperwork....yes, however that is all it is, paperwork. Once it stops raining again I will probably check them to make sure, I suppose one could have already failed if he got a bad one as well.

i am having the same exact problem with my car it has 75000 miles on it and i just did the plugs wires and coils cleaned my maf and am still having the same problem. if i go easy it is hesitant and if i am not easy on it i dont have a problem at all. it is confusing me. i have had the problem for a while. and same thing as him my cel flashes when the car hesitates. it was read as a misfire code did all that and still cant fix the problem. so im at a loss right now and dont know what to do with the problem it is actully starting to piss me off

Update: finally threw a CEL for me and of course it was for "missfire in cylinder 2" yay....so I guess the next step is replacing my coils, plugs and wires.....

yeah mine threw the same code and i changed all of that on mine and it is still doing the same thing it was doing. so im pissed still

Right so have you done any of the aforementioned or are you just going to cry about it until your Dad fixes it?

Mods, Year, Miles on your car?

Well I have tomorrow off so I plan on spending my day working on the car, checking everything I can to hopefully get everything cleaned up and ready to go. This morning she ran perfectly but I know its just a matter of time before the gremlins return. Hopefully a quick cleaning of sensors and a check of the plugs will tell me a bit more.

Thank you guys for the help, I knew that getting a rotory was going to be different and it is very nice to have a community that is actually helpful.

You're welcome.
Post back and let us know how it goes.

Oh and removing the spark plugs is easiest if you remove the front left tire. You can reach straight through the wheel well to access them.
This is also the easiest way to get to the ESS ... well typically the easiest way, imo.
If you have the cold air intake removed you might find it easier to reach down from the top.

actually the PCM opens the SSV solenoid at the same time that the secondary injectors are started