Using Tons Of Gas

[neoiceblink]

I have a 1995 lx400 and since the cold weather gas mileage is all over the board. If above say freezing getting 13-16 city, and when it gets down below freezing getting like 8-10 miles to the gallon. Checked under it for leaks none, don't smell gas, no back firing, no codes, no shifting issues. Things i do notice is little rough when it's cold but after say 10 mins the engine is flawless running, the issues just stared one cold day and has done it every sence. Was getting normal gas like 17-19 in city and 20's on highway over the whole summer. Any help or ideals what to check would be awesome, and also friend said to seafoam it might help what you guys think?

[1990LS400]

Have you precisely calculated the gas mileage over several tank fills (50 to 60 gallons or more) or are you sort of guessing. Have you had this car a long time? Have you been idling the engine more than usual such as to warm the engine or been driving at lower speeds do to ice and snow?

The fuel economy on my 2000 LS400 always declines in winter and it was even worse on the 1990 LS400 I used to have. I think my all time low was about 13 mpg in winter. I've been watching these ups and downs on LS cars for nearly 24 years and have tracked every single gallon of fuel ever put in them.

I have no experience with Sea Foam and am sure that none of the car nuts I know personally have ever used it or would ever touch it. If something is wrong with your car (e.g. the MAF), find out what is wrong and fix that.

[landar]

Seaform is often touted as a 'fix all elixir'. But it is just that...snake oil, IMO. Do not buy it.

As 1990LS400 said, mileage will often drop in the winter months due to cold engines and reformulated gas.

Now, things you might check are temperature related. Does your cabin heater seem to work ok? Is the temp gauge coming up to the proper place in no longer than 10 minutes? If not, your thermostat could be staying open and that results in a cooler engine with a richer gas mixture.

Another might be the temp sensor in your MAF unit. If it is reading low when the engine is really hot then the computer will pour more gas into the engine than needed, thinking it is still cold.

Other things could be a coil that is starting to go bad. However, you should definitely feel roughness in the engine performance. You could also need general maintenance like new rotors and caps, plugs, maybe wires. It is not uncommon to have dielectric breakdown and arcing(especially on these cold, damp mornings) which goes away once the engine warms up due to drying out the components. Any of these could wreak havoc on your gas mileage.

Did you try pulling any codes? How many miles on your car?

Just a couple of places to start.

[neoiceblink]

Things noticed that seem off is noticed more smoke coming out my tail pipes then I have gotten the past 2 winters, its white smoke. The temp gauge works fine will be at full temp within 10mins ideling, also heat works perfect in it no issus taking long to warmup. Also noticed more ticking sound coming from exhaust then past 2 winters also.