Running Bad Around 3000 RPM's

[SKEDDIE]

My car has 95k miles on it. It has new plugs, tb, and the coils only have 17k miles on them. When you get to around 2900 at mid throttle it feels like an old carb loading up. When driving easy it's not noticeable. Put it to the floor and no problems either. I thought it was plugs, so I changed them when I did a cam swap and added headers. It's worse now. Then I thought it was in the tune so I figured when I had the cams tuned they would fix it. It's been at the tuners for a few days with no luck! Any ideas?
Thanks.
Skeddie

 

[JeremyH]

Replace fuel filter and have the injectors cleaned would be my next step.

 

[5.0 Probie]

Like mentioned above. Start with the basics. And why not. 95k miles I bet it needs a few sensors as well. Heck, it could be (If it has them) the converters...

The last time I had this issue it was a plug wire arching and only noticed it around 3500 rpms. It was late at night when I got pissed and pulled over (After trying many things) popped the hood and had a buddy pound the throttle a few times...

 

[SKEDDIE]

No cats, Good fuel pressure. I'll change the filter anyway. And check the injectors.
Thanks guys!

 

[702GT]

Can you datalog the car? I used to have that issue when I was N/A. It would only stumble around 3k at specific throttle positions. I recently discovered my phasers were not functioning correctly. You need to monitor spark, cam angle, and load to see if you have the same issue.

 

[SKEDDIE]

It has the comp phaser lockout kit. It was doing it before the cam swap. Now it's worse with the cams and headers. I'll ask the tuner to see if he has.
Thanks!

 

[702GT]

Are the cams degree'd? Datalog would still show if it was pulling timing.

 

[BruceH]

Is the throttle body accounted for in the tune?

My car has 95k miles on it. It has new plugs, tb, and the coils only have 17k miles on them. When you get to around 2900 at mid throttle it feels like an old carb loading up. When driving easy it's not noticeable. Put it to the floor and no problems either. I thought it was plugs, so I changed them when I did a cam swap and added headers. It's worse now. Then I thought it was in the tune so I figured when I had the cams tuned they would fix it. It's been at the tuners for a few days with no luck! Any ideas?
Thanks.
Skeddie

 

[SKEDDIE]

Yes. The car was running good for about 6 months. Then I started getting this problem. So I changed the plugs and had some coils off another car with only 17k miles when I did the cams and headers thinking it would stop with a new tune of coarse. The tuner told me to ride around with all the emissions turned back on to see if it'll throw a code.

 

[joe_momma]

Yes. The car was running good for about 6 months. Then I started getting this problem. So I changed the plugs and had some coils off another car with only 17k miles when I did the cams and headers thinking it would stop with a new tune of coarse. The tuner told me to ride around with all the emissions turned back on to see if it'll throw a code.

Junkyard coils? I would think this could be a problem if they had been sitting for a while.

 

[AutoXRacer]

I would double check the phasers, timing, and fuel.

 

[SKEDDIE]

Junkyard coils? I would think this could be a problem if they had been sitting for a while.

Na. They came off a buddy's car.
Car has been on the ford IDS and shows no problems with any cylinder.

 

[SKEDDIE]

The car runs fine if you drive it easy. It also runs well if you hammer it! It's only around 3000 rpm's and mid throttle!

 

[eighty6gt]

I'd look for a vacuum leak. How's your charging system? MAF sensor?

 

[SKEDDIE]

Can't find one. I did just have to replace the battery though. I'll have the system checked.
I'll check the maf too.
Thanks!

 

[thump_rrr]

If you had to replace the battery I would check to see that the battery was charged fully on the bench, the alternator is putting out the proper amperage and voltage when needed.
I would also check the 3 plug connector going to the alternator.
This connector may have a wire being held on by only a strand or 2 causing problems.
The proper way to test for a partially broken wire is to use an old headlight as a test lamp since if the wire is weak it will not be able to handle the current of the headlamp.

Was the throttlebody replaced with a stock or aftermarket unit?

 

[SKEDDIE]

So after changing the MAF and Crank PS with no luck. I had my son hold the engine at 3000-3200 RPM's. It was surging about 200 rpms.
I looked at the CMCV arms that connect the rods to the motor and saw that they were jumping from side to side! I reached down and grabbed it and pulled it to one side. The damn thing smoothed right out. I'm guessing the motor is bad.
I've ordered the Steeda Charge motion delete plates.

 

[joe_momma]

Good news

 

[SKEDDIE]

Car is at Piedmont Custom Motorsports getting the new tune to account for the plates. She's been a bitch!

 

[thump_rrr]

If you're still having trouble with it is throw $60.00 towards a pair of upstream O2 sensors.
Mine crapped out at 85,000 miles.