PLEASE help me figure this out! I've posted about the flutter before here. No luck fixing that. My car also shakes a little bit at idle, sometimes enough to carry through the dash and make the dash rattle. It's intermittent but happens at least once every 5-10 seconds. I think these two issues may be related.

I've replaced EGR valve, PCV, MAP sensor. Added LT4KM. Wires are brand new Taylor OVC's, plugs and coil replaced <30k ago (NGK TR-55's and Accel coil). Opti was replaced by a dealer <1 year/10k ago. None of these things helped. I also re-screened my MAF to see if that would help and it didn't. I have new O2's on the way but doubt that they are the problem as they seemed to read alright when I did some Freescan runs.

I took it to the dealer swearing the problem was Opti related(it WAS under warranty) but they looked it over and say that the problem is from the headers hitting somewhere. They are FULL of it because it's most definately an engine condition.

If anyone has any suggestions please help me out! Thanks a lot.

Related mods are listed here:
K&N FIPK, Jet-Hot Longtubes, Custom Y-pipe w/ dual catco cats, DMH E-Cutout, LT4 KM, Taylor 8mm OVC wires w/boot protectors, Accel Coil, NGK TR-55 plugs, new Poly motor mounts, !AIR

 

Exaust hitting the body maby?

 

you could be losing compression. How many miles do you have? Does it run good cold thne run crappy warm?

 

I really doubt the effect is from exhaust hitting, it's definately motor related. That could possibly cause the dash rattle but not the motor "shaking" or flutter.

As for compression- I have 85k miles, car runs pretty much the same cold/warm. It's still as fast as it's ever been at WOT but just doesn't feel right(because of the problems above).

 

does it leak oil? if it is leaking oil out of the timing chain housing then it is leaking right into your opti. also i had a bad dash rattle, and this is how i fixed it: the engine was stumbling and it was causing the throttle cable to bounce up and down and hit the nose of the fire wall. i zip-tied it down to a cable and ran my fingers all the way to the firewall and ziptied any throttle cable that would move when the engine missed at idle. absolutley no noise anymore. the funny thing is the day before i realized this was causing the rattle i broke my dash trying to find the ****in rattle. lol. il learn someday. i guess a rattle for that long will make you do anything, even if it requires breaking the dash to find it. ha

 

I do have something leaking up front but it's so minor(I don't lose oil and it doesn't drip onto the floor) that i never looked into it. Is there any way to test the opti? I want to take it back to the dealer and prove to them that that's the problem(if it is).

Thanks for the rattle fix btw, I'll give that a shot.

 

I have the identical problem as 107, we've talked i think and confirmed that its the exact same symptoms.

To fix the problem I have tried:
Cleaning my MAF
Replaced TPS
Cleaned IAC valve and passages
Rebuilt the whole freakin engine, New block.
Fuel Pump recently replaced
New Plug Wires
Rebuilt Tranny, new TC
Replaced IAT sensor
No leaks of any kind
Replaced O2 Sensors with Bosch.
Replaced MAP sensor

My car is even less modded, all I have is the mods in the sig. Not even a catback or headers like 107.

I've had this problem for a VERY long time(2 yrs +) I have not replaced the opti yet, but it doesnt have the same "opti" dying symptoms everyone else seems to have.

It happens roughly at 50-60mph at light throttle.
It happens at around 60mph for 107 because of his gears I think.
I agree with 107 that its definatly not his headers!

Things we haven't looked into: Replacing/Professionally cleaning Injectors, Fuel Pressure Regulator, ????. Other than that between both of us we've replaced almost everything.

This problem is really driving me nuts. I've scanned the car and everything looks fine, except that when this flutter happens, the MAP (which is working correctly ) basically goes up to barometric pressure, meaning that the engine is just not making power at that range. The car runs great at WOT and anywhere else in the RPM/Speed range. The BLMS and Integrators all seem normal to me.

Some have suggested changing the spark advance tables, but my car is so stock that it really should not need that done!

 

Well, I just wrapped all my sensor wires in conduit to make sure they weren't getting interference from my plug wires, didn't help. I have new O2s on the way. (I heard Jet-Hot coated headers can ruin O2s during break-in, so am giving it a shot, but since you don't even have headers...).

Next to try would be ECT(temp sensor in water pump), and Ignition Control Module. Want to try one of these, toby!?

 

Well I do have them crappy bosch O2's so perhaps i need to replace them with ACDelco's... I've also put washers at my ICT a while back which did absolutly nothing for the flutter =/ But I'll give it a shot chaning the ECT this weekend... haven't done that yet

 

Well, did you scan for knock retard? I am having the same problems with my modded LT1. I am getting 9 degrees of KR when I stand on it in 4th, 5th, 6th gear at 1500-1700rpm.

Could be your problem.

 

I was getting around 0.5-2Degress of knock retard when the flutter occurs according to freescan (assuming its returning its result as degrees).