General Maintenance & Repairs - What is wrong with my car? (acceleration issues)

My car struggles to start!

This is what happens before it starts "normally"
I changed the throttle positioning sensor to see if this was a problem and the car still does this.

I bought a throttle body (with the sensors) and the intake for 40 bucks and put it on. Nothing. Still cranks.

What can be the problem guys? I checked the schrader valve ( i think that's what it's called), pressed it and gas comes out. it cant be the fuel pump. Gas is plentiful I have it at 3/4ths.

I took off the whole throttle body and the car struggles to turn on, but at least it does. Now how is it that the car turns on without the throttle (but the engine revs very high)



Now this is what it's doing

- Car starts, shoots to 1K, then goes down to about 700RPM.
- The car kinda struggles to stay on (but after a few turns, it does.)
- The car accelerates normally if pressed lightly.
- On the 4th speed, I can pick it up to about 80. I change to 5th gear and the max speed is about 90mph. Doesn't go higher unless I pick up the car's speed at 4th gear (maxing it to another speed)
- When you press the accelerator all the way (on fifth gear), the car kinda lags then starts to decelerate.
- When you let go slowly of the accelerator once you have pushed it in all the way, the car accelerates as you let go of the accelerator.

Unplug the maf and iac when you start it. See what happens.

Unplug the maf and iac when you start it. See what happens.

IAC? MAF? What are those?

Idle air control valve and mass air flow sensor.

IAC? MAF? What are those?
Time to buy some LS1 magazines & do some reading. I applaud your fearless efforts to tackle your car but you really need to find a buddy with more knowledge to help you with this. Good Luck.

Idle air control valve and mass air flow sensor.

Okay I should've specified. I have a 1996 V6 Firebird.

I have 2 different sensors on the throttle body: The throttle body positioning one and the mass air flow (I think that's the squarish looking one). Is the Idle Control one the one connected to the intake?

Can you explain the "acceleration issues listed in the hyphens please?

When's the last time you checked your plugs wires and oil.

Bad Egr valve can cause hard start/ poor running condition. also Fuel pressure at the rail when at idle may be enough but at 90mph is it maintaining the pressure needed? don't rule out the pump or regulator until your certain. my 2 pennies worth. good luck

When's the last time you checked your plugs wires and oil.

The plug wires? When I changed the spark plugs (took 10 freaking hours!)

The oil? Yesterday just before I went on my 100 mile trip

Does your Ses light come on or blink at you when it's struggling?

Does your Ses light come on or blink at you when it's struggling?

Nope. I think the previous owner removed the lights for "Check Engine" and the "Service Engine Soon."

I took the car to the mechanic about 2 months ago and he told me someone removed the light. The gauge cluster lights all come up except for the Check Engine one and the Service Engine Soon light. This is at start up. I can get you guys a video of the problem but my phone has horrid video quality.


Thanks.

My friend, it sounds like it may be in your best interest to have somebody knowledgeable with you while troubleshooting this issue. Not belittling you at all, it's just that there are several possible issues that could be causing this and you would save a great amount of time. Then going forward, you've got that knowledge under your belt and if you have the same issues you'll know what to look for. :nod:

My friend, it sounds like it may be in your best interest to have somebody knowledgeable with you while troubleshooting this issue. Not belittling you at all, it's just that there are several possible issues that could be causing this and you would save a great amount of time. Then going forward, you've got that knowledge under your belt and if you have the same issues you'll know what to look for. :nod:

They'll trouble shoot it but SOME mechanics are shady. I don't see why mechanics can't just tell you everythign that's wrong with the car instead of saying "This is wrong with it and you're gonna have to buy this. The total is going to be 400 dollars plus labor."

I just don't trust anyone with my car except my dad.

Most places have a diagnostics fee. if your gonna take it somewhere, ask around and find a reputable shop. There are some dirt bags, but you should be able to find a decent Shop. Sometimes its best to let someone else do the dirty work. also the data stream on a good scan tool is priceless when your stumped! A good shop will have more Diagnostic equipment and can save you time and money in the long run.

look for some local fbody members in your town. they should be able to help you out trouble shoot it with you.

look for some local fbody members in your town. they should be able to help you out trouble shoot it with you.

I live in Houston if that matters.


Help me guys. Or PM me.

They'll trouble shoot it but SOME mechanics are shady. I don't see why mechanics can't just tell you everythign that's wrong with the car instead of saying "This is wrong with it and you're gonna have to buy this. The total is going to be 400 dollars plus labor."

I just don't trust anyone with my car except my dad.

unfortunately if every mechanic just told you what to buy to fix your car they wouldnt be in business very long. knowledge has no price.

along with you plugs and wires, how old is the fuel filter how about he air filter they could be clogged and not flowing enough fuel or allowing air flow. do you have access to a fuel pressure gauge or a scan tool - they are very helpful with today's cars.

Most places have a diagnostics fee. if your gonna take it somewhere, ask around and find a reputable shop. There are some dirt bags, but you should be able to find a decent Shop. Sometimes its best to let someone else do the dirty work. also the data stream on a good scan tool is priceless when your stumped! A good shop will have more Diagnostic equipment and can save you time and money in the long run.

Well said. Not all mechanics are snakes. Hell, they are getting less and less common, people don't put up with that sh!t anymore - everyone does their homework nowadays. Just remember this - be very thorough with your service writer on your issue, otherwise it could lead to them diagnosing the wrong issue. And be prepared to pay some diag time if you really want the problem found.

Well said. Not all mechanics are snakes. Hell, they are getting less and less common, people don't put up with that sh!t anymore - everyone does their homework nowadays. Just remember this - be very thorough with your service writer on your issue, otherwise it could lead to them diagnosing the wrong issue. And be prepared to pay some diag time if you really want the problem found.

^^^ This.
If you do have fellow LS1 Tech members in your area, having them help you troubleshoot would be the best as far as gaining knowledge for the future. If there isn't anybody in your area, having a respected mechanic help you out will save you a ton of $$$ and frustration. You'll just have to decide if you want to throw parts at it until it's fixed, or if you're in over your head and just need a little help. 'Aint no shame in it. We all start somewhere brother.

^^^ This.
If you do have fellow LS1 Tech members in your area, having them help you troubleshoot would be the best as far as gaining knowledge for the future. If there isn't anybody in your area, having a respected mechanic help you out will save you a ton of $$$ and frustration. You'll just have to decide if you want to throw parts at it until it's fixed, or if you're in over your head and just need a little help. 'Aint no shame in it. We all start somewhere brother.

Like I said, I'm in Houston. Any fellow tech members from Houston or CollegeStation/Bryan are more than welcome to private message me.

you're in houston aka f-body heaven. If you want your car fixed you have to take the initiative and talk to people in person.