1995 Buick Roadmaster Sedan 350 cui, LT1 from Germany


A perfect car for every day


For about half a year, I have had the check engine light coming on sometimes, when the engine is going back to idle, for example: cruising and slowing down to a traffic light to stop. Sometimes, the light disapears during hard acceleration. At a new engine start, the failure is always gone. There are no trouble codes stored. Funny.

At 40 000 miles I had to replace my oxygen sensors, because the right one caused a rich mixture (black smoke).

Absolutely no other problems.

General Comments:

This is a perfect car for everyday driving, takes between 8 and 14 litres of gas for 100 Kilometres. Very good for a car with this power and weight.

You can outperform BMW, Audi and Mercedes up to 110 MPH. Then the speed is limited.

A quiet car for doing long trips.

As far as I know, we have 3 Roadmaster Sedans running here in Germany.

Would you buy another car from this manufacturer? Yes

Review Date: 24th November, 2001

18th Sep 2003, 16:55

Limited top speed? The bad is that your car is set from the factory for use with "R" rated tires (106 MPH/170 KPH) or "S" rated tires (112 MPH/180 KPH). The good news is that you are in an ideal location (Germany) to reprogram your PCM for higher speeds (consider the Hypertech unit). Although I am in Southern California, my boat has easily reached 135 MPH (~215 KPH) after I performed the reprogramming task (15 minutes). My car has been reprogrammed to "Z" rated tires (190+MPH/300+ KPH) and I run "Z" rated tires on Impala SS wheels. One day I will go to an isolated area and see if 150 MPH is possible.

The top speed is limited from the original factory programing and was only determined by the speed rating of the factory tire options. If the B-Body car came factory equipped with VR rated tires, the speed was set to 149 MPH or 240 KPH (normally the setting for an Impala SS).

The check engine light can be many things! However, the most overlooked and least expensive upgrade for all 94-96 LT1 engines is the LT4 Knock Module (GM P/N 16214681). Once you upgrade to this module, many little "knock module generated soft codes" will stop. Replacing this unit will result in about 2 weeks of driving time where the PCM reprograms its self to this module. Each day you drive the car it just get faster and smoother. For $40.00 (in the US) it is the best upgrade!

I have three cars with LT1 based engines and I just love these machines. My current project is close to being finished and I will be able to "blow-past" most cars with my set up. Hint: A 1993 T/A with a 1996 OEM LT4 engine and special mods.

Good luck with your Autobahn rocket!

29th Jan 2005, 11:00

Thanks for your tips.

We already tuned a friends 95 limited sedan with the Hyper-Tech to 300 HP and a speed limit of 240 km/h.

It does the 240 easily, running on 17 inch tires.

I ordered my Hyper now, will see.

Got some problems with Opti-Spark, solved them now.

Needed a new starter, they are lousy. My RM has 73000 miles now, is still a reliable car.

Seems the S E S comes from low voltage, when I switch off the AC/Heater unit, it dissappears.

3rd Nov 2009, 06:36

To original poster...

That check engine light may be because of a dirty EGR valve. Had the same problem with my 95 Fleetwood. Car would stutter sometimes at a stoplight or when slowing down. Only threw a check engine light once for a split second.

Check it out...