Lexus GS (1997-2020) firing order — diagram & guide

As a larger executive sedan in the Lexus lineup after the smaller IS model, the GS has been around ever since the 1990s. During that time, drivers could choose between different engine options including four-cylinders, V6s, and even a V8 engine used in high-performance versions.

So, we wanted to help all the owners maintain their GS engines regardless of their engine type. This guide on the Lexus GS (1997-2020) firing order will shed some light on the engine firing sequence for every engine in particular, as well as the cylinder configuration.

Second-generation Lexus GS (1998-2004) firing order

The second-gen Lexus GS model featured the only six-cylinder straight engine along with a few V8 options. The engine selection was later expanded starting with the third-gen model, so let’s see what the main firing order specs are:

Lexus GS 3.0L Straight-six firing order

The Lexus GS 3.0L Straight-six firing order is 1-5-3-6-2-4 and it’s a pretty unique engine among all the Lexus options used in this model. The thing is – it’s a straight-six instead of all the V6 engines used later on, and it’s an engine derived from the Toyota Supra’s 3.0-liter turbo straight-six.

In other words, the engine’s cylinders are placed in a straight order from 1 to 6, with the first cylinder being the front-most cylinder, and the sixth one being the cylinder at the rear end of the engine.

Lexus GS 4.0L firing order

As the first V8 GS model, the Lexus GS 4.0L firing order is 1-8-4-3-6-5-7-2 and the same goes for the other V8 engines used in the GS. The engine’s cylinders are laid out with the odd cylinders numbered 1, 3, 5, and 7 front to rear on the driver’s side.

Passenger’s side cylinders go in order 2, 4, 6, and 8 front to rear, and it’s relieving that all the V8 engines used in this model come with this same cylinder configuration, so you can’t go wrong.

Lexus GS 4.3L firing order

The Lexus GS 4.3L firing order is 1-8-4-3-6-5-7-2 just as it was for the 4.0-liter engine. What’s more, the engine’s cylinder configuration is also the same as for that engine, and cylinders are ordered 1, 3, 5, and 7 on the driver’s side, and 2, 4, 6, and 8 on the passenger’s side.

Third-generation Lexus GS (2005-2010) firing order

The third-gen Lexus GS model came with a completely swapped engine lineup except for the 4.3-liter V8 that was still offered from the second-gen model. One of the biggest differences is that there was no straight-six engine offered in this generation, but rather a V6 instead.

Lexus GS 3.0L V6 firing order

The V6 3.0-liter engine was introduced with the third-gen GS after the initial 3.0-liter straight-six from the second-gen model. This one brought two major differences in terms of the firing sequence and the cylinder arrangement, so the Lexus GS 3.0L V6 firing order is 1-2-3-4-5-6.

As for the cylinder arrangement, this transverse engine has cylinders 1, 3, and 5 laid out left to right in the upper cylinder bank. On the other hand, the lower cylinder bank has cylinders 2, 4, 6, and 8, also ordered from left to right.

Lexus GS 3.5L firing order

Yet another V6 has been used in this generation model of the Lexus GS, and it’s a larger 3.5-liter engine. Still, the Lexus GS 3.5L firing order is 1-2-3-4-5-6 so it remained the same as for the 3.0-liter engine. There’s one notable difference between these two engines, and that’s the cylinder placement.

While the previous engine is a transverse one, this one is a regular V6 and that means the cylinders are ordered 1, 3, and 5 on the driver’s side, and 2, 4, and 6 on the passenger’s side.

Lexus GS 4.6L firing order

The third-gen model still featured a 4.3-liter V8 engine, but there was another option added for this model and it’s a 4.6-liter V8. The Lexus GS 4.6L firing order is 1-8-7-3-6-5-4-2 with cylinders 1, 3, 5, and 7 being on the driver’s side, and cylinders 2, 4, 6, and 8 on the passenger’s side.

All the cylinders from both banks are ordered front to rear in the same way as for the 4.3-liter engine.

Fourth-generation Lexus GS (2013-2020) firing order

The fourth-gen GS model saw a lot of change with the new generation as all the previous V8s were removed from offer, and there was the “F” version 5.0-liter engine added instead.

It’s also the first time that Lexus GS was powered by a four-cylinder turbo, along with a 2.5-liter V6 and the 3.5-liter engine which we already discussed.

Lexus GS 2.0L turbo firing order

As the lowest-displacement GS engine, the Lexus GS 2.0L turbo firing order is 1-3-4-2. This engine is a straight-four powertrain powered by a turbocharger and its cylinders are numbered 1 to 4 in a straight order from front to rear.

Lexus GS 2.5L firing order

The 2.5-liter V6 replaced the previous V6 engines from earlier generations, and the Lexus GS 2.5L firing order is 1-2-3-4-5-6. As you can see, the firing order is the same for all the V6 engines, but this one isn’t like the transverse options like the 3.0-liter one in terms of cylinder placement.

Instead, cylinders 1, 3, and 5 are on the passenger’s side front to rear, while cylinders 2, 4, and 6 are ordered front to rear on the driver’s side.

Lexus GS 5.0L firing order

As the final engine option, we’ve got the 5.0-liter V8 from the “F” version of the GS, and that one was the highest-capacity V8 engine ever used in this model. So, the Lexus GS 5.0L firing order is 1-8-7-3-6-5-4-2, and cylinders 1, 3, 5, and 7 are located on the driver’s side, front to rear.

The cylinders 2, 4, 6, and 8 are on the passenger’s side, also ordered front to rear just like with the previously-mentioned V8 engines.

Our take

Well, there you have it – we’ve addressed the firing order and cylinder layout of every Lexus GS engine option. So, regardless of whether you own a four-cylinder, six-cylinder, or V8 engine, we are confident you’ll be able to diagnose misfires and notice failed spark plugs and coils.