WhiteLS1Formula

Car is a 99 LS1 formula A4. Stock, except for hypertech programmer and a cutout. (I didn't program the hypertech, the car came that way) I should probably re tune it to stock, but i don't feel like spending the money at the moment...I know it will be expensive...

Anyway, the car is just acting weird. While accelerating sometimes, the car cuts out for a 1/2 sec and goes normal again. (Generally coming off of a turn) It seems like the fuel gets cut or something? It's strange..Although, at WOT the car is fine and has never done it. The only other issue with the car is that sometimes it bangs the rev limiter when going from 1st to 2nd. I'm thinking that might be the hypertech? How can i fix some of these issues? Any advice?

Thanks again.

Paul Bell

iTrader: (9)

Fuel pressure issue? Changed the filter lately?

WhiteLS1Formula

Actually no, i haven't changed the fuel filter...Hmm, that might be a start. Fuel filters are cheap too...

USMarine0351

Your Throttle Position Sensor (TPS) may be giving a bad signal to your ECM. The resistive grid in your TPS may be a bit worn, you can not accurately test this without a graphing multimeter or oscilloscope. But you can try putting you car in a manual gear and slowly depressing the throttle while accelerating to find that certain point. If it is your TPS, the worn part of the grid is typically at the throttle angle where you set your cruse control, and you will have to replace the entire TPS.

WhiteLS1Formula

What do you mean "find that certain point." It just does it randomly and not all the time.

y2k_ta

iTrader: (80)

Did you happen to get the Hypertech programmer with the car? If so, the stock tune should be in the programmer.

USMarine0351

You said only while your accelerating your having the problem, but at WOT its fine.

The point that your throttle is depressed in relation to the throttle position sensor. If your TPS is worn in a certain area of the resistive grid it will send a false signal to your computer, making you computer think you just let off the throttle when really your at (ex. 70%) throttle. Which in turn cuts your fuel.

You would have to test it with a graphing multimeter to be sure though.

eseibel67

iTrader: (10)

Fuel filter and TPS are good things to check.

Problems that only show up in turns are sometimes caused by bad wires that are getting shifted around by the force of the turn.

Hopefully you find the problem before it comes to that.

eseibel67

iTrader: (10)

Also, reprogramming to stock tune is not that expensive.

Where are you located?

WhiteLS1Formula

I'm located in St.Pete Florida.

No, i did not receive the tuner when i purchased the vehicle.

I also don't know when the car had a tune up last...Could this also potentially be a problem?

eseibel67

iTrader: (10)

Your condition doesn't sound like a tune up, but it's good practice to pull a plug and take a look. I'd say #3 is probably the easiest.

You shouldn't have a problem finding a tuner in St Pete to start you off with the basics. The Florida section will point you the right way.

WhiteLS1Formula

Hmm, didn't realize their was a Florida section. I'll have to go and check it out.

I just want to make sure the car is running at an optimal condition before pursuing any modifications.