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Car starts but wont accelerate at all. Idles great

Tiny
SAVAGECOWBOY
  • MEMBER
  • 1992 PONTIAC BONNEVILLE
  • 280,000 MILES
I have been having small problems with this car for a while. Just recently I was having a driving problem it would stutter and die at 2000 rpm intermittently my first thought and diagnosis was a faulty maf with this repaired the car ran great for about a month then it wouldnt go over idle with out stalling out my fuel pressure was a little strange so I replaced my fuel pressure regulator but that wasnt the problem, it was sitting for two months so I decided to clean out the intake with some seafoam nopw it goes a bove idle but not above 2- 2.5 grand and it backfires intermittently I am down to thinking either severely clogged fuel lines or my coils or icm is bad please help the only testequipment I have is a dmm
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Saturday, March 3rd, 2012 AT 1:12 AM

16 Replies

Tiny
SATURNTECH9
  • MECHANIC
  • 30,870 POSTS
What about a clogged exhaust have you checked the exhaust back pressure yet?Also have you checked for codes?
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Saturday, March 3rd, 2012 AT 1:17 AM
Tiny
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Oh also the fuel filter is 2 months old fuel pump is 2 yrs old so r the battery cables spark plugs show no signs of oil or misfire or over heat. One of the coils was replaced when it died about two years ago oxygen sensor is about 7-8 months old
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Saturday, March 3rd, 2012 AT 1:44 AM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,870 POSTS
Have you checked fuel pressure also have you thought about maybe water in the fuel etc?Any codes in the computer?
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Saturday, March 3rd, 2012 AT 2:51 AM
Tiny
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  • MEMBER
  • 8 POSTS
I checked the fuel pressure before I replaced the fpr thats why it got replaced fuel pressure didnt jump at all when a vacuum line was removed. Only code was from my misadjusted tps that has been fixed. I dont have a way to check backpressure but the donut in the exhaust was just replaced 3-04 months ago because it was leaking visibly, the rest of my exhaust tubes are welded and have no cracks or holes(smoke test performed)
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Saturday, March 3rd, 2012 AT 4:58 AM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,870 POSTS
Do you have a cat on that car?
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Saturday, March 3rd, 2012 AT 5:13 AM
Tiny
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Yes
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Saturday, March 3rd, 2012 AT 5:14 AM
Tiny
SATURNTECH9
  • MECHANIC
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You could have a plugged cat unbolt the cat from the exhaust pipe and see if the engine revs up.
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Saturday, March 3rd, 2012 AT 5:23 AM
Tiny
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  • 8 POSTS
I cant its welded I would have to cut it off
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Saturday, March 3rd, 2012 AT 2:11 PM
Tiny
SATURNTECH9
  • MECHANIC
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Drop the pipe at the manifold start it and see if it revs up right?That will take the cat and exhaust out of play. Then atleast you can rule that out.
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Saturday, March 3rd, 2012 AT 5:26 PM
Tiny
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Ok I droped the pipe and the problem is still there
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Monday, March 5th, 2012 AT 12:11 AM
Tiny
SATURNTECH9
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What was the fuel pressure after replacing the fuel pressure regulator?Also have you checked to see if the fuel filter is clogged or restricted?
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Monday, March 5th, 2012 AT 12:24 AM
Tiny
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Fuel filter was changed 3 months ago dont know pressure cause I dont have a pressure tester at my house
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Monday, March 5th, 2012 AT 12:36 AM
Tiny
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You said you changed the fuel pressure regulator beacause of the fuel pressure. So thats why I asked what is the fuel pressure?We have to rule that out also auto rents fuel pressure gauges.
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Monday, March 5th, 2012 AT 12:49 AM
Tiny
SATURNTECH9
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Also when you pull the vacuum line off the fuel pressure regulator the fuel pressure will only change if the engine is running.
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Monday, March 5th, 2012 AT 12:50 AM
Tiny
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I checked it at school when I could still get it there and I pulled the vacuum line when the car was running
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Monday, March 5th, 2012 AT 12:52 AM
Tiny
SATURNTECH9
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Alright so now we need to know what the fuel pressure is without it running.
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Monday, March 5th, 2012 AT 12:59 AM

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