Engine misses, horrible mileage

[crazyhorse]

Hello all you V6 gurus

Car: 1995 Olds Cutlass Supreme SL
Engine/Trans: 3.1 Auto
Miles: 203,xxx MI

Problem: The engine has what feels like a dead miss, and is getting in the 15mpg range. The SES light isn't on. The miss has gotten more severe lately, and feels like it's on 4cyl. I bought a useless code reader from a chain store, so I can't say if there are any stored codes.

Question(s):
1. What code reader can I beg/borrow that will read the codes on a '95. The application guides list '89-93. Then in '96 they went OBD2. I know that if it were a '94 I could jump terminals to check codes. This doesn't work.
2. Could I be fighting a mechanical problem, if so, what does it sound like?

Thanks in advance for any help you can give.

[TazMan]

Autozone reads codes for free but I don't know if it matters whether you have OBD 1.5 or OBD 2. I would call first and ask. My 95 3100 Century was OBD 1.5 so I'm guessing that's what yours is as well.

[crazyhorse]

Yeah, a bit of extra reading in the archives & I found that info. My local 'Zone won't read the obd1.5.
Like I said tho the SES light isn't on, so dangIFiNO.

I do know that I'm becoming less & less of a GM fan, the longer I own this car.

[JoeMechanic]

Here's what I would do in this order with that heap of 203,000+ miles.#1 check fuel pressure at the schrader valve fuel rail.I think it should be in the 41-47 psi range at least.#2 check engine compression every cylinder should be within 10-15% of each other at least 150 psi..the higher the better.To check compression pull every spark plug out,disconnect the crank sensor wire on your control module(so you don't get a surprise zap).Open the Airvalve(throttle body) wide open with a large screwdriver to keep valve open.Harbor Freight Tools sells a quick disconnect compression and also leak down testers for under $30.There is no sense quessing usually fuel injection cars especially the 3.1 have problems with injector clog.If compression is good and fuel pressure is good then its either a bad plug.wires,coil,Ign control module,02 sensor.Injector clogged.This engine may be tired at 203,000 miles so start with compression test and fuel pressure test it can save you alot of time and hassles knowing the condition of this motor first.You can list the results here and either I or issac hayes or someone else could decipher what they mean..good luck!.

[crazyhorse]

Thanks Joe, your advice sounds dead on. I'll get on that 1st thing in the am. I own a compression tester already, and I'll get the results posted. Fuel pressure....can I check it with a tire guage? I don't own the "proper" tool.

I had already decided to get back to basics tomorrow, and check the fuel filter, & spark plugs. A compression test is just one more basic check.

I can't swear to the mileage on the motor, as it has junkyard markings on it. I'd guess at most 150k. The odo. shows 203k

[crazyhorse]

OK new fuel filter today, no guts no glory. To describe the problem better it's like the engine is in a bind. it simply won't rev. It barely gets to the 4k cutoff in park.
There is about 3-5degrees of slack in the timing chain. I'm guessing that's to the point of being kaput.

[flame suit]Shoot the import guy :P It's been a LOOOOONG time since I messed with a pushrod engine.[/flamesuit]

[gpse3400]

other that it misfireing is it doing anything else?