Can only use part throttle

[rivet]

Perhaps someone knows what I can do. My car is great on the highway, very quick, but I can't use full throttle. I use most of it them back off a bit to get best acceleration. I thought it was because of not enough octane. Ok I thought. But today I noticed that as I accelerated hard in first the car slowed up dramatically in about the same throttle possition, 2/3 to 3/4 ish. The other gears are the same but not as drasitic. It would be an awesome car if it had full throttle. I can back out of the throttle and it surges again. Strange I thought. I resently checked the Double Platinium plugs and changed the fuel filter last year. It has a Holley Air charger on it. Mileage is about 27- 30 at illegal speed. Oh stock wires.
So what is it? Throttle possition? Boost level? Spark blowout? Fuel preasure? Octane? Exhaust? Does anyone else have this problem? Im stuck.


94 RT TT 110000km
Air charger
Double platinium plugs, Stock gap
Stock otherwise

[Fast Eddie]

wow thats tough. I have never had a problem like that, so i dont know how much help i can be, but I would start simple and maybe pull the Y-pipe off the throttle body, then get someone to press the gas pedal from inside and watch that the blade inside the throttlebody is working properly.

You are at stock boost level? maybe your boost control solenoid is broken and you are overbooosting, so the car is pulling timing, to save itself? dont want to scare you, but if it is throttle dependant, there is a good chance boost has something to do with it.
If you can get your hands on a data logger, you can check what is going on in the engine, and also make sure all the injectors are good.

[fou]

What boost are you running at?
BDC or stock?

[rivet]

Well the boost is at stock level (13?) and I dont think its over boosting mostly because I dont think the acceleration is that strong, but Ill put a gauge on it to check. I doubt if the car will sqeal a tire any time, so therefore boost is low, just a thought.
I was down to the GTA last year and found some 94 octane gas (you guys are lucky) and the car felt stronger but mostly the dead spot in the pedal moved closer to wide open. One other point is that I havent had the car over 245 mph. That seams to be the limit on pump gas. Data logers are very rare up here Im afraid.
Thanks for the suggestion I will try a few other things. I wish I could put the car up against another one. That would tell a lot.

[Fast Eddie]

I have a logger that i could hook up to your car and go for a drive and see whats going on if you come down to the toronto area again. might be better to have an idea of whats going on before you take it in and they start replacing stuff.

[Diablo]

Ever changed or tested your o2 sensors?

[BigBoi]

Originally posted by Diablo
Ever changed or tested your o2 sensors?

how do ya test them bitches?

[BigBoi]

Originally posted by BigBoi
how do ya test them bitches?

use a multi meter???? what should I see? How do I know if heater is workin?

[Malice]

My thoughts would be on the TPS or fuel pressure.

1. fuel pressure - youi may have clogged injectors or your pump may not be getting proper voltage so when you go WOT you run a little lean and the cars computer cuts the boost.

2. TPS - it may not be properly sensing your pedal position. Could be for a couple reasons, lack of voltage, too much voltage, etc., but it may be the cause.

But do the cheap things first. Check your o2 sensors like these guys said, run some injector cleaner and check your voltage where you can. That may help narrow it down.

Later