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7th third gen found a real gem but has issues

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Old Jul 18, 2015 | 12:05 AM
  #1  
BigDom's Avatar
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Joined: Jun 2010
Posts: 43
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From: LONG ISLAND, NY
Car: 1989 Trans Am GTA
Engine: 5.7L 350CI L98
Transmission: 700R4
7th third gen found a real gem but has issues

So I found my 7th third gen if call it a NYC barn find (it was sitting in a parking garage for 10 years) so it hasn't started or moved in those ten years

We put in a battery and the engine cranked but wouldn't start we checked and figured the fuel pump was shot so we changed it and it started right up

Now it's running extremely rough when I press the gas it hesitates badly till 3k rpm and blue smoke is coming out of the exhaust at start and during revs

Also if I leave it idling it idles perfect but then shuts off and as off tonight it won't restart

It's a 350 with 50k miles

Any good ideas where to start?
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Old Jul 18, 2015 | 01:35 AM
  #2  
tealman92's Avatar
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Joined: Mar 2002
Posts: 998
Likes: 19
From: Ontario, California
Car: 1992 Z28
Engine: 383
Transmission: 700R4
Re: 7th third gen found a real gem but has issues

Injectors and fuel pressure regulator.
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Old Jul 18, 2015 | 05:31 AM
  #3  
CatmanFS's Avatar
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Joined: Aug 2009
Posts: 332
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From: this car
Car: 85 Z28
Engine: 93 LT1
Transmission: Auto
Axle/Gears: 3.73 01 SS
Re: 7th third gen found a real gem but has issues

Spark plugs, cap, rotor, air filter, fuel filter, fresh gas, clean battery terminals, clean everything. Change the oil, change the trans fluid, do a solid inspection and replace everything that's broken or needs it. Give it a shot, then you'll know if the problem is something like head gaskets, blown rings or something of that nature. Good luck.
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Old Jul 18, 2015 | 10:44 AM
  #4  
Damon's Avatar
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Joined: Sep 1999
Posts: 7,072
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From: Philly, PA
Re: 7th third gen found a real gem but has issues

Yeah, full tune up on both the fuel system and ignition. Hopefully the injectors aren't clogged up (they probably are after sitting that long), but do the easy stuff first. It needs it anyway. And you need to start eliminating what it CAN'T be to help you diagnose what it CAN be causing the rough running.
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Old Jul 19, 2015 | 04:53 PM
  #5  
TylerSteez's Avatar
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Joined: May 2013
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From: CT
Car: 86 Trans Am WS6
Engine: 383 stroker
Transmission: 700r4
Axle/Gears: 9 Bolt Torsen 3.70
Re: 7th third gen found a real gem but has issues

Do what everyone has said about the full tune up, then put premium gas in and run it for a while, that should clear what's clear able in the injectors. Sea foam the motor by sucking it through the brake booster vacuum hose will clean out some engine debris. The hesitation when revving is a sign of a bad maf sensor, they can be problematic and costly

Edit: is the computer pulling any codes?

Last edited by TylerSteez; Jul 19, 2015 at 04:56 PM.
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Old Jul 19, 2015 | 05:52 PM
  #6  
Birdstheword's Avatar
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Joined: May 2009
Posts: 727
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From: Riverside (Wood Crest) , CA
Car: 1988 Pontiac trans am
Engine: 305
Transmission: 700R4
Re: 7th third gen found a real gem but has issues

Don't forget the valve seals !
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Old Jul 19, 2015 | 06:22 PM
  #7  
TylerSteez's Avatar
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Joined: May 2013
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From: CT
Car: 86 Trans Am WS6
Engine: 383 stroker
Transmission: 700r4
Axle/Gears: 9 Bolt Torsen 3.70
Re: 7th third gen found a real gem but has issues

Also go over and replace all the vacuum hoses, they usually are the difference between a good running tpi and a horrible running aggravation
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