poor throttle response

[Drake57]

persists in my 1992. I have new deatshcwerks replacement injectors, new fuel pressure regulator, new fuel filter, fairly new fuel pump. Problem is worse when car is not warmed up, on sudden throttle opening, it tends to bog, sometimes backfires, or bucks. If it happens, I can let off, then open throttle again, and it will pick up and run, but it is really too cold shouldered.

Before replacing regulator, at times it would barely run. Now it runs well, except at times when I really need it, under quick throttle opening.

I'm beginning to suspect fuel pump controller, IIRC, fuel pump may run at three different speeds depending on load conditions.

Is there any good test for controller?

Thanks, Drake.

[GoadQ45T95]

You can jump one of the pins on the controller to make it run at high speed(not a permanent fix) see if that clears the issue for you. Use the search button its mentioned numerous times. Thats about the only way off the top of my head I can think of to test it.

[goody90q45]

From the trunk, unplug the connector from the FPCU (located under the rear parcel deck) and run a jumper wire from the pin shown in the pic to a good ground point (the metal frame in front of the fuel tank). The FPCU will only run in the fastest speed until the connector in reinstalled.

[Drake57]

FPCU had crappy solder joint on corner pin, connector plastic burned where pin dresses through. I re flowed all pins, will try it in morning. Thanks for the picture.

[3Q Jay]

it will work (unless you blew the cap or a transistor---did you smell burnt electronics?

need to not only re-flow but white (okay, black if you wish) wire the ground for long term fix.

[Drake57]

Re flow improved but did not eliminate lousy pickup. Jumping corner pin as in pic above provides same performance as re flowed FPCU. So it's better, still just not what this kind of car should deliver, though. I'm pretty sure it's lean, adding enrichment with NDS DataScan override mode improves pickup.

[Shawn_hollen]

My 99 had poor throttle also mine was secondary throttle position sensor but it had that code. Didn't see in any of the post about a throttle code so probably not it but worth a look I replaced mine and fixed it got all acceleration back.

[sheikhnbake]

My '97 Q45 lost about 50% throttle power when the knock sensors went bad. Replaced them and then the car drove like a dream again.

[squaremeal]

My 94 had poor throttle response until I replaced the alternator. Before I replaced it I brought it down to Autozone and the old one tested good the first time. The guy tested it again and the second test came out with it being bad. I replaced it (not the easiest job) and the response was much better.

[HansCC]

I had to go through all the fuel system - cleaned injectors, fuel rail, replaced fuel filter, cleaned throttle body, changed plugs, changed all 8 coilpacks - It's all back now -