First off this car has the old LG2-LG3 3.8, not the 3800.
He bought it used about 3 months ago, has 231,000 KMS on it so about 135,000 miles.
It runs uneven, if u rev it in park then let go of the throttle is seems the idle gets worse after reving it up. So we pulled the plugs, they look new, AC delco plugs and wires, wires look very new and still have fresh di-electric grease in them.
This car gets TERRIBLE mileage, on the highway the car should get 28-35 in overdrive, yet it gets maybe 12-15 on the highway. It can be hard to start, 3 trys usually, sometimes it starts first time though. Doesn't seem to matter if its hot or cold, the problem has only gotten worse since he bought it.
The air filter is new.
I wonder if it could be the fuel filter, or 02 sensor, is there any way to scan it for codes, i know my Bonneville had the "flash feature" i wonder if this one does too.
Any insight would be greatly appricated by him.
Thanks!

I say go for an o2 sensor. Its not too much, but can always help. I know when my car is acting up, I put a roll of paper towels [the cheap kind, trust me on that], by the tail pipe. When the car is running good, the paper towels should only come out dirty. If the car is running too rich, or isn't firing on all cylinders, then it will come out wet [this is only effective when the car is cold, so the cat doesn't burn off all the extra fuel. Post back your results..


-justin

Also , the old off center engines had faster wearing timing gear, plastic gear teeth, ect. Worn timeing gear messes up the relationship of the crank and cam sensor signal. High milage cars that have not had timing set changed have symtoms of eratic idle and somewhat "rough" idle. This sloopy timing set could also be whats causing your " idle gets worse after reving it up*".

These were not real smooth at idle anyhow, thus the reason for the balance shaft after 1988 with the LN3-C.

Changing the timing gears, chain, tensioner and camshaft button on these older engines is considered necessary at any time after 90,000 miles. I have heard of engines breaking them as low as 7?,000. The good news is the gears can be replaced with steel toothed gears.

Im not telling you this is the problem but its something to think about.

*reving it up - not advised on high milage old style engines with original timing gear.

Actually to think of it, my Parents bought in 1993 a 1986 Buick Park Avenue LG2, had 60K on it when they got it, in 1997 at like 110K the car wouldnt start one morning in the garage, dad found out it was the timing chain and gear that were both very worn...the Buick dealership said it was actually common on the early 3.8s to do this over time.


Anyways, my uncle figured it was something to do with timing, he then asked were the distributor was on it....umm hate to break it to yah, but, no such thing on this! lol
I think a tune up would do it some good anyways...and a damned oil change, its over due by more than 1000K miles...lol