Acceleration problem?

Tiny
RWALBROEHL
  • MEMBER
  • 2003 CHEVROLET S-10
  • 2.2L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 70,000 MILES
Had previous issues with service engine light. Scanner revealed purge solenoid valve, small vacuum leak, catalytic converter. Replaced fuel filter, sealed vacuum leaks, changed purge solenoid valve. Ran complete engine conditioner by Lucas through system. Driven it a few miles in the neighborhood 8 times after resetting the light and now service engine light comes in. However, when slowly accelerating speed can increase to around 45 MPH but if I step in it will not accelerate and hangs. If I try to accelerate fast, its low-speed same thing. Trying to rule out transmission once home I put it in park and slowly increased speed and around 4000 rpm hangs up and drops rpm. Does that rule out transmission and maybe a different problem? Thanks
Wednesday, July 9th, 2025 AT 5:45 AM

3 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 52,273 POSTS
Yep, this sounds like a classic fuel pump issue. I would confirm with a fuel pressure test which you can rent the kit from the auto part store for cheap or free. Here is a guide to help as well:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Fuel Pressure (Key ON Engine OFF) .................... 379-427 kPa (55-62 psi)

Please go over this guide and get back to us if you need instructions to replace the pump?
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Wednesday, July 9th, 2025 AT 7:25 PM
Tiny
RWALBROEHL
  • MEMBER
  • 112 POSTS
I did previously check the fuel pressure with a gauge from AutoZone and it was approximately 60lbs. Left it connected and drove around the block and never dropped but didn't get over 30mph. I had a previous service engine light months ago showing cat converter problem. Bank one low efficiency, purge solenoid, small evap leak. Changed purge solenoid, fixed two vacuum leaks, installed new fuel filter. I have driven it 8 times since then after resetting the system by disconnecting the battery and reconnecting and no service lights or warnings however still only accelerate with no problem if I very slowly step in the gas to increase speed. If I open the throttle too fast, it bogs down. Was still thinking maybe exhaust restriction maybe with partially clogged cat. I alco ran complete engine conditioner by Lucas through it. Running high test gas also. What's your suggestion. I thought about taking off upstream O2 and if it accelerates better than it would definitely be the cat.
Thank you
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Thursday, July 10th, 2025 AT 8:05 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 52,273 POSTS
Yep, that was what I was going to suggest, here is a guide to help as well:

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

You can also loosen the exhaust head pipes as well, it will be loud but if the exhaust is clogged the engine should have full power.
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Thursday, July 10th, 2025 AT 9:49 AM

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