I have the mods in signature. I went to an 1/8th mile track last night and competed in the Sportsman class. The 1/8th mile times in my signature are from this same track, only a few months ago. I have gotten the cam tuned since then so it should have ran better. I was not spraying. I went to a 1/4 mile track 2 weeks ago and ran 13.3 at about 107 MPH, which I wasnt too upset about bc I couldnt get the car to hook and my trap speeds were still pretty decent. Well I was excited about going to this 1/8 mile track bc there track prep is pretty decent and I knew I could hook there. Well, first run I wheel hop some and I run a 9.00 at about 78 MPH. I was like alright what the hell. Next run, perfect launch with no spinning at all, still only run 8.89 at about 78.5 MPH. I got my ticket bc I was excited to see what my 60ft would be bc I had a great launch and what do I end up getting? A freakin 1.98 60ft with a dead hook launch!!!!!! I could really tell the car wasnt pulling like it normally does and I was pretty upset as to why my car was running so crappy. Alright, well here are the symptoms.
1. At very low RPM's idle-about 2500 I will get a slight surge and I can feel the power coming back and then it goes right back out.
2. Right when my car hits 40mph and goes into overdrive and I give it a small amount of gas, the whole car just vibrates like crazy.

Anyone who has had this problem before please help out. I have put way too much time and effort into this car to have it running this crappy. Thanks alot, Dustin.

 

what kind of valve springs do you have?

 

LT4 valve springs. Everything was fine after the cam install which was about 4 months ago. This problem has just happend within the last week or so.

 

Maybe a bad plug.........or plug wire. It's usually the simple stuff.

 

Well I thought it might have been one of my plug wires that was laying against the header and was a little discolored but I just changed that one and it made no differance, the car missed out once as I was pulling out for the test drive and it still vibrates real bad in overdrive and still over-all didnt feel as powerful. I am going to borrow my friends coil and ICM and see if that cures it. If not then I guess I will move on to plugs, and if still no change, I guess I will have to see about the opti. I cant see it being my opti bc the thing only has like 5k miles on it at the most and is only a year and a half old and there was no large amount of liquid spilled on it prior to this happening. Oh well, guess i will just have to keep playing the guessing game and see what happens. Any other suggestions would still be greatly appreciated. Thanks, Dustin.

 

Well here is the list of things we have replaced so far, I didnt purchase any of these parts bc we have a crap load of extra parts laying around that we know work.
1. Maf Sensor
2. IAT sensor
3. Coil
4. ICM
5. TPS
6. Replaced plug wire that I thought was burnt
I pulled one of the plugs and it didnt smell like fuel and I was told that it was they way that it was supposed to look. The car still runs the way it did, still seems sluggish. The vibration in overdrive seems to have reduced slightly. I am going to hook a scanner up to it sometime and hopefully it can tell us something. thanks, Dustin.

 

Check your fuel pressure..... just something else to take out of the equation.
I say this as I am having my own fuel pressure problems.

 

Can the LT4 springs take that lift? Im on stock rockers with the CC305 and i know if i wanted some 1.6's i would need to get different springs cause the LT4's would bind.

 

The LT4 springs are good up to .525 lift. I run the same springs on my hotcam and haven't had a problem. It depends if the lift on the cam was measures with 1.5 or 1.6 rockers. I don't know how they rate lift, but if it's rated on 1.5's he could have a problem

 

The hotcam is measured at .525 using 1.6 rocker arms. Having said that, I have had this cam in my car for about 4 months now, the car ran great the first time I had it to the track after the cam install. My problem got alot worse today tho for a while. I started the car up for work and pulled out and the car was just going crazy on me. I would give it gas and the motor would just cut out and drop RPM's and then come back alive and then go crazy again and my car was shifting at weird spots and I didnt think I was going to make it to work. Well I got there and when i was leaving work the car missed out again but no as bad and then half way home the car was back to normal and was driving fine. What does this sound like to you guys? Thanks, Dustin.

 

Fuel pump is on it's way out. Did you listen to CrystalSS? Since fuel pressure relies on an electric motor, the motor can and does weird things when it goes bad. Pressure can drop to a very low level and cause many problems, then return to a good level and everything is fine.

Did you let the fuel level in the tank get too low? That's the major killer of fuel pumps.

At least let us know you eliminated the fuel pressure (when the problem occurs) so we can move on to something else.

 

We tested fuel pressure today. At started idle its at about 38-40 psi and when its revved up to about 5k the pretty will go up to about 42psi and then when the gas is released the pressure drops down to about 31-32 psi and then comes back up real quick to idle numbers. I dont know if this is normal or not so I could use some more advice. Shoebox said that it sounded normal to him so I am not sure what to do at this point. Just yesterday I started to have some wierd problems with my tranny too. Sometimes the tranny will rev up too far before shifting( it still shifts hard but is just a little delayed) and when close to WOT the tranny wants to short shift on me. Then of course when I get back in the car to drive away again it wont do it on this trip. Oh, and sometimes now I have a high idle and sometimes I dont. I dont have any idea what the heck is happening to my car right now. Peace, Dustin.

 

Pull ALL the plugs and look at them,not just the easy ones.
Then if one looks suspicious I would look under the valve cover on that side.
I would gap the plugs at .035 before reinstalling and see if it will take the load off of the opti and wires.

Are ya sure the rotor in the opti is OK?

 

The opti is about a year and a half old and has about 5 k miles on it if that. I know I have gotten some coolant on it at some times but not a whole lot. I also had my shift points raised to about 6300. I read already that the opti rotors cant handle being spun that high.

 

Yeah sometimes people rotors fail but the car usually won't even run after that. Opti's can handle 6000+ RPM's pretty much anyone with heads and cam spin 6000+ RPM's and most of us are running opti's.