Car bogs down and dies when given gas (Page 1/2)
lafemmefiero73 JUN 28, 06:53 PM
My 1987 Fiero GT (stock V6 automatic) bogs down and dies when the gas pedal is pushed after being stopped for a few seconds, like at a stop sign. We've cleaned out the throttle body and replaced the spark plugs and throttle position sensor. Any ideas of where to go next? Thank you!
Patrick JUN 28, 07:57 PM

I'd start with basics... such as fuel pressure.
bootdsc JUN 28, 08:50 PM
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[This message has been edited by bootdsc (edited 06-28-2020).]

bootdsc JUN 28, 08:51 PM
After everything I went through working on the 86 gt to figure out why it had the same issue I wish I had started with simply checking fuel pressure.

Harbor freight sells two fuel pressure checker kits, the cheaper of the two is all you need and it's only $20ish.

Deleting the pulsator was the only thing my car technically needed to fix it.
lafemmefiero73 JUN 28, 09:54 PM
Thank you for the replies! Looking more into the pulsator issue, that sounds like what I'm running into. It looks like the pulsator connects to the fuel pump output and fuel feed line. I'm curious as to anyone who has bypassed this - is the pulsator actually inside the tank, or right outside? How easy is it to bypass in your garage with basic tool? Is it doable without dropping the fuel tank?
Patrick JUN 28, 10:51 PM

The pulsator is often replaced with a short piece of submersible hose (not regular fuel line). The tank needs to be dropped.

First things first.. test the fuel pressure.
lafemmefiero73 JUL 17, 07:10 PM
Thank you! I tested the fuel pressure with the Harbor Freight kit. Right when the fuel pump turned on, it went to 40 psi and then sat at 38 psi. The Haynes manual says normal range is 40.5-47 psi. Is mine close enough to in range that it's probably not causing the issues?
Patrick JUL 17, 07:21 PM

quote
Originally posted by lafemmefiero73:

40 psi and then sat at 38 psi. Is mine close enough to in range that it's probably not causing the issues?



That should be fine.

As a test, try temporarily unplugging the electrical connection of the MAP sensor and see if that makes a difference.
lafemmefiero73 AUG 15, 11:20 AM
Thank you! I tested for vacuum leaks and didn't find any obvious ones. I used a scanner, and the voltage on the MAP sensor read at 3.76 whether the car was at idle or given throttle. It never changed. I replaced the MAP sensor with a new one, and it still had the same problem bogging down and reading exactly at 3.76, no variation between idle and throttle. It sounds like the next step in testing would be to unplug the wire to the MAP sensor to see if the reading changes, and if it does that would indicate the wiring is fine? Thank you!
cebix AUG 15, 12:25 PM
Is your EGR good? On the duke it seems to be a common bogging source, not sure about the V6.