Ok, this has been happening for a long time and I can't figure out what it is. My problem is sometimes when I press the gas in any gear, the car seems like it's being held back by something almost as if I am towing something, then all of a sudden it goes away and pulls like normal. I have MSD wires and coil pack and it still does this and I have changed the plugs numerous times. I am turbo now, but it also did this long before I was turbo.

there is a number of things that could be causing this, when does it do it? (warm engine, cold engine, after a long cruse? )

not boosted, but I've had similar problems, usually seems to be after I've been cheap and used cheap station gas. a good coctail of stuff usually clears it up for me.

1 5gal gas can
fill with:
1-2 cans BG44k or equivalent
1qt Lucas Upper Cyl lubricant
1/2 1pt bottle StaBil fuel stabilizer
1 bottle Heet fuel drier
1qt octane booster

Top off 5gal can with highest octane GOOD name brand gas you can find (I prefer conoco/phillips myself) add to nearly empty tank, run till the dummy light comes on.

I've always had amazing results doing this. I do it about once a year.

Hmmm I'll have to try that. It happens more when the car is cold but it still happens when it's up to operating temps. I don't know it's just bugging me and holding my car back big time when I want it to go. Then it just goes away instantly and my car takes off. I don't know, it's just weird.

What plugs do you recommend for a boosted 420A?

NGK Spark Plugs BKR7E (#6097)

I always noticed more hesitation when cold at first then as time went on it got more noticable even when hot, and finally it was so bad the car just sucked anywhere between 2-5k rpms. coctail almost completely eliminated it the first time. then got a professional injection flush and it completely went away for a long time, now if it starts again I just know to spend a few extra bucks and I can make it go away for a good while. I've heard that it's just older worn injectors getting plugged up and some new ones would clear it up. don't know how reliable that info was tho.

Ok thanks, I think I'll try the cocktail deal first and see what happens. In fact, I'm going to go out and buy all that crap right now and I'll get back to you guys later.

Well I put it in yesterday and after using most of what's left in the gas tank, it still does it and nothing really changed.

hmmm, pull your plugs and look at those, do a compression test while you're there. since the problem is more noticable when cold I'd do the compression test at both cold and hot engine temps. normally you just do it hot.

Edit: any CEL's?

Sorry I ignored this thread for a while but relating to the last post, no there are no CEL's. I am almost certain that it is the ecu because on my logger at idle it reads 5.9% throttle and at full it only reads 29%.