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1989 L98 350 Rough idle absolutely no power. Dont let me get smoked by a GEO!

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Old Feb 14, 2013 | 04:45 PM
  #1  
lambo5150's Avatar
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From: Kansas City
Car: 1989 Firebird Trans Am GTA
Engine: 350 L98
Transmission: 700r4 shift kit and corvette servo
1989 L98 350 Rough idle absolutely no power. Dont let me get smoked by a GEO!

Would appreciate any help, thoughts, or ideas.
After a winter nap outside under a car cover I woke my car up and she has no power. Already had trips to mechanic but its not getting anywhere and im running low on money. Last trip I had EGR replaced maybe helped a bit but something is terribly wrong here

After reading several threads, some ideas I came up with possibly being wrong are:
vacume leak in engine
bad compression
fuel pump
the injectors
pcv valve
But I do not have much mechanical knowledge.

Basically car shakes crazily at idle 800rpms ish, reving up it slows down a little. Car stinks when driving and a slight tick i believe to be coming from exhaust manifolds, I plan to upgrade to shorty headers though after this is fixed.

I put together a little video of what it was like last year compared to now again any thoughts are appreciated.
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Old Feb 14, 2013 | 07:14 PM
  #2  
camarito's Avatar
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From: sussex county, NJ
Car: 84 Z28 / 11 genesis coupe
Engine: 355/210 heads/275deh/Proform 750 DP
Transmission: 700r4/B&M 2400
Axle/Gears: 02, allu.axle, 3.42, posi
Re: 1989 L98 350 Rough idle absolutely no power. Dont let me get smoked by a GEO!

Almost sound like your plug wires are arching and causing a miss fire, did you check the plugs?
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Old Feb 14, 2013 | 07:27 PM
  #3  
wishoradream's Avatar
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From: Oklahoma
Car: 1982 Z28
Engine: 388 SBC
Transmission: TH350 Lockup
Axle/Gears: 3.42
Re: 1989 L98 350 Rough idle absolutely no power. Dont let me get smoked by a GEO!

I def hear an exhaust leak, I believe?
You replaced the plugs and wires according to your video?
Compression test is where I would first start
It's possibly the injectors.
But run a compression check on it, make sure all your wires are pushed on securely
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Old Feb 14, 2013 | 07:28 PM
  #4  
wishoradream's Avatar
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From: Oklahoma
Car: 1982 Z28
Engine: 388 SBC
Transmission: TH350 Lockup
Axle/Gears: 3.42
Re: 1989 L98 350 Rough idle absolutely no power. Dont let me get smoked by a GEO!

The "shaking" sounds like it's missing. Either not getting fire or gas to one of the cylinders, I bet when you do the compression test you find your problem
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Old Feb 14, 2013 | 08:11 PM
  #5  
lambo5150's Avatar
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From: Kansas City
Car: 1989 Firebird Trans Am GTA
Engine: 350 L98
Transmission: 700r4 shift kit and corvette servo
Re: 1989 L98 350 Rough idle absolutely no power. Dont let me get smoked by a GEO!

Thanks guys. When the weather gets warm again ill have the compression test done. A few days ago I noticed the lower radiator hose must have gone bad right when i put it into park, so once I get that fixed ill get a compression test and let you know if that fixes it. I had spark plugs done last year but couldn't have driven more than 500 miles with the new plugs and wires, and I had the mechanic check for a misfire when i took it up earlier this year. the plugs are Bosch Platinum3. It is weird though, the old wire that came on the car all had heavy insulation wrapped around them, a mechanic told me though that it would only make things worse. I ran injector cleaner once on the car and when i get the tank a little dry i plan on trying it again.
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Old Feb 14, 2013 | 08:14 PM
  #6  
wishoradream's Avatar
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From: Oklahoma
Car: 1982 Z28
Engine: 388 SBC
Transmission: TH350 Lockup
Axle/Gears: 3.42
Re: 1989 L98 350 Rough idle absolutely no power. Dont let me get smoked by a GEO!

Plugs SHOULD be fine, but that doesn't mean you didn't get one of those factory mistakes. I replaced plugs in a ford ranger one time, within a week the threaded end of the plug, and the end the wire goes on had completely separated from each other. I thought the motor was about to blow up, but found out what it was later. I'd just make sure all the boots are on really good.
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Old Feb 14, 2013 | 08:18 PM
  #7  
wishoradream's Avatar
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From: Oklahoma
Car: 1982 Z28
Engine: 388 SBC
Transmission: TH350 Lockup
Axle/Gears: 3.42
Re: 1989 L98 350 Rough idle absolutely no power. Dont let me get smoked by a GEO!

and in the correct places.... I can't count how many times people have brought me crosswired cars...... Not directed at you, but it's worth a look!
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Old Mar 8, 2013 | 05:03 PM
  #8  
lambo5150's Avatar
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From: Kansas City
Car: 1989 Firebird Trans Am GTA
Engine: 350 L98
Transmission: 700r4 shift kit and corvette servo
Re: 1989 L98 350 Rough idle absolutely no power. Dont let me get smoked by a GEO!

Thanks for the info guys. I took it into the shop today to have lower radiator hose fix and to look at its problems. I told them after having other look at it they though it was a misfire or bad compression. They said they didnt think it was a misfire because the longer it ran the worse it got also a misfire wouldn't make it even run as bad as it is. They acted like I needed a new engine or at least new heads. I guess next step ill have someone who specializes in engines look at it, and get their opinion. I'm between jobs right now so cant afford anything really now.
It idled at 400rpms after I started it, it died on my when I hit the throttle. At a stop light I held the brake and tried to rev it up and rpms wouldnt really build floor it at the light and it slowly started moving. rpms are bouncing around at the 2500 range, and will build up once I am moving just no power behind it when it does.
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Old Mar 8, 2013 | 08:52 PM
  #9  
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Re: 1989 L98 350 Rough idle absolutely no power. Dont let me get smoked by a GEO!

Go to auto zone & rent a fuel pressure tester.
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Old Mar 8, 2013 | 09:01 PM
  #10  
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From: arden nc
Car: 92 camaro rs
Engine: 3.1
Transmission: 700r4
Axle/Gears: rear disc non abs
Re: 1989 L98 350 Rough idle absolutely no power. Dont let me get smoked by a GEO!

Originally Posted by ex-x-fire
Go to auto zone & rent a fuel pressure tester.
is your water pump leaking on to the timing chain cover?
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Old Mar 10, 2013 | 01:13 PM
  #11  
lambo5150's Avatar
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From: Kansas City
Car: 1989 Firebird Trans Am GTA
Engine: 350 L98
Transmission: 700r4 shift kit and corvette servo
Re: 1989 L98 350 Rough idle absolutely no power. Dont let me get smoked by a GEO!

No leaks from the car. Maybe Ill try to get that fuel pressure test done. I would probably have to have a mechanic do it though.
It may not be related but I did have a lot of air pressure in the tank whenever i opened the cap (which I s why I drilled a few small holes in it) also when I pour gas in, it.. gargles a lot in the tank.
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Old Mar 10, 2013 | 03:01 PM
  #12  
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From: Rockville Centre, NY
Re: 1989 L98 350 Rough idle absolutely no power. Dont let me get smoked by a GEO!

how long did the car sit without running? Just for the heck of it check the resistance on your injectors both hot and cold. Just another issue to rule out

www.southbayfuelinjectors.com
516-442-4707
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Old Mar 11, 2013 | 04:04 PM
  #13  
lambo5150's Avatar
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From: Kansas City
Car: 1989 Firebird Trans Am GTA
Engine: 350 L98
Transmission: 700r4 shift kit and corvette servo
Re: 1989 L98 350 Rough idle absolutely no power. Dont let me get smoked by a GEO!

The car has been saiting for about 3 months so not too long. all 8 injectors read about 17.8 ohms. I'm going to look up what they should be at but I am guessing since all 8 are the same they are probably right. Thanks for the idea though, I've heard those injectors it came with are pretty problematic and its the first test I was actually able to do myself. Will probably have a mechanic do a fuel pressure test later this week.
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Old Mar 11, 2013 | 04:38 PM
  #14  
lambo5150's Avatar
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From: Kansas City
Car: 1989 Firebird Trans Am GTA
Engine: 350 L98
Transmission: 700r4 shift kit and corvette servo
Re: 1989 L98 350 Rough idle absolutely no power. Dont let me get smoked by a GEO!

THE GTA LIVES!!!!!!!! while out with the multimeter and remembering how the gauges were shorted with the cruise control I remember I switched fuses with something in the fuse box while testing the gauges fuse. Well I decided to test all the 10 amp fuses and when I pulled out the injector fuse I had an open. My face lit up wondering if this 5cent piece could be giving me all these problems and lost sleep, I swapped it out and she was back! I am surprised the car would even run without that fuse working. Shouldn't a mechanic been able to figure it out to be a fuse? Regardless thanks a lot guys, my own stupidity I guess, but I still learned a lot more about these cars by it.
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