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Hi, new member here. I have a 99 Firebird with a 3.8l and automatic transmission. I was coming home from work and the car just died on the highway. My initial guess was that the fuel pump had given up the ghost. A couple days later, I tried to start the car in the driveway after pulling the codes. The only thing that came up was p1518.

The car started fine and I drove it around a little and all seemed fine, so I deleted the code. The next day, the car started and idled, I gunned the accelerator a bit and it sputtered and died. Now cranks but will not start. New codes are p1516,p1221, p1220 and p1120.

I am now guessing that the throttle body is no longer responding to input. Would that be a fair presumption? Can these fly-by-wire TBS be rebuilt or am I looking for a replacement?
 

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Welcome to the forum.

Besides the throttle body codes, you also have a fuel pump code in there. So I would put a fuel pressure gauge on the fuel rail fitting and check to see fuel pressure is too low to run.

Download the 99 service manual in the 4th gen tech section. It has a driveability and emission section with all the codes explained. Why they set, what happens when they set, and troubleshooting.

I'm not really up to date with the later 4th gens but my guess is the throttle body with drive by wire can't be rebuilt by the owner. Parts are probably not available. You would have to by the whole drive by wire assembly. Or maybe even the complete TB.
 

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Ramblin' Wreck
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DTC1518 means the pcm could not communicate with the TAC controller module. Some possible causes are 1) intermittent ground or power connections or 2) intermittent connector at the TAC module or 3) defective TAC module. I would check the connection at the "TCS Batt" fuse in one of the underhood fuse/relay boxes and the "Elect Throt Cont" fuse in the other underhood box. Remove the fuses and plug them in again. Next I would unplug the connector at the TAC module and re-plug it. It is just above the accelerator pedal.

Since the TAC module controls the throttle body, it seems unlikely to be a problem with the throttle body itself, but they do occur frequently and I have heard of strange things like this before.
 

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Thanks for the tips, sea dog and GaryDoug. Will follow up and report back! Your assistance is much appreciated. I frankly am a clutch and carburetor type of guy and all this modern remote controlled computerized stuff has me way out of my comfort zone. Thanks again!
 

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Discussion Starter · #5 ·
I have no fuel pressure. None. Looks like my initial equipmentless diagnosis was correct. I cannot fathom how a fuel pump costs $400!!! Looks like the car will be sitting awhile.
 

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Ramblin' Wreck
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Does that price include installation? Be aware that you can cut a trap door in the floor just above the pump and remove it from the top. Most shops quote a full job including removing the tank and a lot of other things in the way. There are plenty of pumps for far less. ( I have no knowledge of this one specifically, it is typical for eBay)

http://www.ebay.com/itm/99-02-Chevrolet-Camaro-Pontiac-Firebird-Fuel-Pump-Assembly-for-3-8L-engines-/271702992635?fits=Model%3ACamaro

Even if it fails too quickly, the trap door would make replacement easier.
 

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Discussion Starter · #7 ·
No, that was the purchase price quote from the parts store. That was not a replacement quote from a repair shop.
 

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I believe with your 99, you have to buy the whole fuel sender assembly, instead of just a pump like older cars. On my 95, I can buy just the pump for $179 or the complete fuel sender assembly for $379.

Something to ponder, when your ready to buy, most auto parts stores have on line ordering. Every couple of months they offer 25% off with free shipping for ordering on line. At least autozone & advance do this. You can save $100 on your fp by ordering on line when discounts are offered.
 

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Discussion Starter · #11 ·
I could live with that. It would save me from having to swap connector pigtails to the new style. Then again, the fuel gauge has never been worth a dang, so maybe I'd be better off with a complete sending unit.
 

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Discussion Starter · #13 ·
Well, my fuel pump finally showed up last night. Popped it in and the car fired right over. New pump and filter installed this morning and all seems right in the world. Thanks so much to the members and admins of this site! I sure do appreciate your time and wisdom!
 
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