1998-2002 Firebird and trans am rpo codes

Changes By Year for 1998, 1999, 2000, 2001 and 2002 Pontiac Firebirds and Trans Ams

Thanks to JRP of www.ls1tech.com


1. Had differnet casting heads which had perimeter and valve covers.
2. Ignition Coils were mounted to the valve covers one at a time.
3. The water temp gauge actually works.
4. 98's do have an oil life monitor, they just don't tell you anything when its time for a change. You can find it in Auto-Tap
5. WS6s had single outlet exhaust (all others had duals)
6. Steering wheel controls were completely different part with indentations on the buttons, and were better built
7. Only year that Purple, Gold, and Green were available
8. Some very early Trans Ams came with LT1 style headrests
9. Rear hatch release was poorly designed and often caused problems releasing mechanism
10. Early model 98 Monsoon stereos didnt have capability to control 12-disc CD Changer
11. 1998-1999 automatic transmission LS1s could be started in 1st gear even with the shifter in 2nd. Starting 2000, if you put the shifter in 2, it would start off in 2, even from a stop.
12. 1998-1999 LS1 cars had a smaller throttle body cam, which caused the throttle to open to WOT faster than 2000+ cars
13. 1998 cars had 28 lb fuel injectors from the factory
14. 1998-2000 cars had a larger cam than the 01-02 cars
15. 1998-1999 cars had more restrictive exhaust manifolds
16. 1998-2000 cars had an LS1 intake with EGR
17. 1998 and some early 1999 cars had blue outside rear view mirrors (TA/Formula only)
18. 1998 only LS1 blocks had a much smaller cylinder sleeve that only tolerated a .005" hone
19. Last year F-body to use the old 15.5 gallon steel fuel tank.
20. Only year LS1 F-body to contain a gascap with a tether long enough to actually hang from the fuel door while open
21. Only year LS1 F-body to not contain the famous GM black box used in the event of an accident to record up to 5 seconds of pre-crash data
22. 1998 only cars had a different PCV system with the PCV valve located above the passenger side valve cover
23. 1998 most cars did not have an idle adjustment screw on the throttle body. Some 98 cars do have the idle throttle stop set screws.
24. 1998 cars have a completely different PCM from 99+ cars
25. A production shortage of F-body cams caused the use of a C5 cam to be installed in F-body LS1s for a very short time
26. 97-98 LS1's used a paper water pump gasket. The only gasket that isn't reuseable
27. SSs did not ALL go to SLP starting in 98. Y2Y was the RPO code that sent them to SLP for additional options
28. SS option did not "include" the Synthetic oil package, it was a SLP only Option


1. 1999-2000 cars switched to 26 lb fuel injectors
2. Cylinder heads and valve covers redesigned to have center bolts instead of perimeter bolts. Other than that, the heads were the same.
3. Redesigned cylinder sleeves that allowed for a small bore, up from .005" in 1998 models.
4. Midyear model change to a cheaper steering wheel audio control button without finger indentations, and cheaper built
5. 1999 cars continued the LS1 intake with EGR provisions
6. 1999 cars continued more restrictive exhaust manifolds and larger cam
7. Only year that Hugger Orange was available (Camaro only)
8. 30th Anniversary Trans Am available with special blue and white paint package and blue clear coated WS6 wheels
9. Switch to larger 16.8 gallon plastic fuel tank to meet new emissions requirements.
10. Gascap tether was shorter and could no longer be used to hang on the gas door when open.
11. Company wide change added black boxes to record up to 5 seconds of data before a crash
12. Rear hatch release was redesigned with stiffer spring that released the hatch better
13. Water temp guage was redesigned to work basically as a dummy gauge and only show an overheat condition.
14. An oil life monitor was added to all LS1s, thus changing the gauge cluster a little to show the oil life reset swtich
15. 1999-02 cars had a different PCV system with the valve located to the side of the intake manifold
16. Early production 1999 Trans Ams still had the blue outside mirrors, but a midyear change went to the non-tinted ones
17. 1999 there was the color "Medium Blue Metallic" which was available on both the Camaros and Firebirds. Only one year of that color


1. Redesigned exhaust manifolds for new emissions standard actually flowed better and created a little more HP.
2. 2000 continued use of LS1 Intake, EGR, smaller cam, and 26 lb fuel injectors
3. Added rear child seat safety hooks to interior per federal requirements
4. Very early run of WS6s had "salad shooter " style rims. A production change switched back to standard 5-spoke WS6 rims.
5. Camaros got redesigned 10-spoke base rims, and SSs came with new 10-spoke rim design
6. First year of Monterey Maple Metallic paint
7. Charcoal (grayish) interior was replaced with Ebony (almost black) leather interior
8. Cloth interior cars got new rainbow colored cloth patterns
9. Camaros only got the Pontiac steering wheel with optional audio controls
10. Throttle body cam was increased in size to slow the speed at which the car reaches WOT
11. Automatic transmission cars were reprogrammed to allow a car to start off in 2nd gear from a stop when the shift lever is put into 2.
12. The last year a WS6 Formula was offered
13. Starting 2000 intake lids contained a seperate breather filter
14. 2000+ Camaros came with body colored mirrors instead of black ones like 98-99


1. A small percentage of 2001 and 2002 LS1s actually had LS6 blocks which had a different part number and a darker metal cast
2. Starting 2001, all LS1s came with an LS6 intake manifold without an EGR system
3. Advertised HP output was changed from 305 to 310 on base LS1s and from 320 to 325 on WS6s and SSs
4. 2001-02 cars have a smaller cam from the Vortec truck engines to increase low end torque
5. 2001-02 cars had 28 lb fuel injectors like the 98 cars (albeit different part numbers)
6. WS6 cars had a redesigned 5 spoke rim which was more wavy
7. WS6 cars got less suspension upgrades from a base Trans Am suspension than previous years
8. Manual transmission cars all came with the Z06 clutch

2002 - Last year of the F-body

1. 35th Annivesary edition of the Camaro, and Collectors Edition Trans Am available
2. 2002 LS1 head gaskets redesigned. The new ones are a pressed metal, as opposed to the graphite ones and are no longer specific to the side of the car theyre installed on
3. 2002 cars continued with the LS6 intake, 28 lb fuel inectors and smaller truck cam
4. 2002 continued the use of an LS6 block in some LS1 F-bodies
5. A factory supported optional 345 HP option could be ordered from SLP
6. Manual transmission cars continued use of the Z06 clutch
7. Some 2002 model F-bodies came with a revised rear view mirror that had the map light buttons on the bottom, rather than the front.

Specific 2001 - 2002 Changes

from WARD'S AUTO WORLD, January 1998:

The small block legend continues in model year 2001 with more horsepower and a host of refinements, including several engineered for the new LS6 V8. Yet the bottom line hasn't changed. The LS1 takes a back seat to no V8 engine, and remains one of the best bargains in the automotive world.


Camshaft from LQ4 6.0-liter V8 (Vortec 6000) Truck Engine

Eliminate Exhaust Gas Recirculation (EGR)

Increased Volume Fuel Injectors

Increased Flow Air Cleaner with Larger Mass Air Flow sensor (MAF)

Pup Catalytic Converters

Cast Exhaust Manifolds with New Gasket

Reduced Tolerance Main Bearings

Revised Oil Level Tube and Indicator

Extended Maximum Oil Change Interval

Two-point Water PumpVapor Vent

Sleeveless Coolant Sensor

Revised Powertrain Control Module Calibrations

Revised Rocker Cover Castings


Powertrain engineers found an elegant, cost-effective answer when the platform team asked for a five-horsepower increase in the 2001 LS1: They borrowed a billet-steel camshaft from the LQ4 Vortec 6000 truck engine. The new cam has more advance and different timing, delivering more torque lower in the rev range. Coupled with an improved air cleaner developed for the LS6 V8, the new cam increase horsepower by five in the Firebird.

Application of the LQ4 cam produced a valuable side benefit: elimination of the Exhaust Gas Recirculation (EGR) system. The new cam creates more valve overlap, or periods when both intake and exhaust valves are partially open at the same time. Increased overlap allows the LS1 to meet National Low Emissions Vehicle (NLEV) certification without EGR. Removal of EGR reduces engine plumbing and potential leak sources.

New fuel injectors increase maximum fuel delivery to 3.55 grams/second. The injectors were developed specifically for the new Corvette LS6 V8, but have been applied to the LS1 as well. Shared injectors mean assembly efficiencies, and open the LS1 to further power increases in the future.

The LS1 benefits from other improvements developed primarily for the LS6, including Delphi's high-volume version 1.2 Mass Air Flow sensor, with integral inlet air temperature sensor. This MAF Sensor increases intake volume and allows the Powertrain Control Module to adjust for optimal performance at a given air temperature.

  • I have received MAF tables for '98-'99, '00 and '01-
    '02; the only differences are in how the upper end is
    populated (blank or flat-line values above 11500Hz).
    The "guts" of the tables are the same, and the part
    number is the same too from all accounts.

    Now the 'Vettes did change, like going from an
    F-body style to a screened 85mm to a descreened
    (Z06 anyway).

    - jimmyblue

Firebirds equipped with the LS1 borrow a page from the Corvette by adding a pair of pup converters for model year 2001. Mounted upstream from the primary Catalytic Converters, the pumps heat more quickly and reach emissions light-off temperature before the primary converters. The pups help all 2001 LS1s meet Low Emissions Vehicle (LEV) requirements.

Pup converters also allow the LS1 to be fitted with cast iron exhaust manifolds developed for the LS6. These manifolds increase exhaust flow slightly and reduce cost considerably. They are also more durable than the dual-wall stainless manifolds on the 2000 LS1. Other things equal, cast manifolds take longer to reach full operating temperature than stainless, but with the pup catalysts light-off is still achieved in less than 20 seconds. A new gasket allows the manifolds to be used interchangeably between the LS1 and LS6.

Reduced tolerances in the crankshaft main bearings mean a more precise fit. The result is an increase in long-term durability and, just as importantly, a reduction in something known to engineers as "cold knock"--a slight slapping noise from the engine before it reaches full operating temperature.

New computer algorithms extend the oil-change interval. The Powertrain Control Modulerecords engine temperature and length of operation at a given temperature; with new data on real-world customer use, engineers have adjusted the software to allow longer intervals before an oil change is indicated. The LS1 has a maximum permissible interval of 10,000 miles with recommended conventional lubricant.

The number of Water Pump vapor vents has been reduced from four to two, reducing cost. Experience with the LS1 has shown that two vents are sufficient to help maintain proper pressure and control coolant aeration.

The coolant temperature sensor, supplied by Packard Electric, uses a plastic insulator to protect electrical leads in the brass housing, rather than a rubber sleeve. The new sensor reduces the possibility of assembly rejection or shorting in operation.

With the hardware adjustments, the Powertrain Control Module has been recalibrated to maximize performance and efficiency and ensure certification to National Low Emission Vehicle (NLEV) standards.

Rocker covers have revised bosses, allowing the covers to be used interchangeably between car and truck small-block engines and enhancing assembly efficiency.

The LS1 achieved Low Emissions Vehicle (LEV) status in California for model year 2000, thanks to higher capacity catalysts on the Firebird and revisions that increased flow through the Air Injection Reaction (AIR) system in all applications. Cars equipped with LS1s were also fitted with On Road Vapor Recovery (ORVR) systems. The LS1 continues the grand tradition of one of the most important engines in automotive history--the original small block V8. While it shares its 4.4 inch bore centers with the first small block, the LS1 has introduced a host of advanced technologies to the overhead-cam V8, including all-aluminum construction, a thermoplastic intake manifold and drive-by-wire electronic throttle.

The LS1 retains its high-efficiency gerotor oil pump, which is driven off the front of the crankshaft. Benefits of the gerotor design include improved low temperature delivery and better performance, due to lower parasitic power loss.

"This engine obscures the line between overhead cams and overhead valves. There's no distinction anymore. The LS1 excels in reducing mass, package size and cost, with outstanding performance and NVH that's competitive with overhead-cam V8s. Doubters said we couldn't do everything--particularly meeting LEV—with overhead valves. We've proven them wrong." --John Juriga, Total Integration Engineer, LS1/LS6 V8

The LS1 has wowed the business and enthusiast press, and found a spot on the WARD'S AUTO WORLD list of the 10 Best Engines in North America each year since its launch, because there is no arguing with results. This V8 exceeds customer expectations with outstanding overall performance at modest cost to both the customer and the corporation.

"Tire-trashing torque is what you want in a world-class sports/GT car, and the LS1 delivers--RIGHT NOW—when overhead cammers are still spooling up. That such torque and horsepower come with more refinement than one has a right to expect in nearly six liters of thumping V8 proves how effectively the old small block has been redesigned."


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