1998 Ford Taurus SE with "Bumpy" Idle.

[1sttruck]

"...given it a good blasting with CRC Lectra Clean"

I'd suggest only using the CRC 'electrical cleaner', as one of the CRC 'electra' cleaners melted some connectors.

Try a vacuum gage to see how steady it is at idle. Try pulling a hose on the intake at start up to see if it gets better or worse, at another time try some starting fluid. Listen to the fuel injectors to hear if they're working ok. Hook up a timing light on each plug to see if it's firing. The newer cars also have 'pre codes' available on testers, where they haven't tripped the check engine light but they're candidates for doing so. A Sears $80 or so tester can read them, while the the older cars just need a jumper wire and reading a blinking check engine light.

The older Taurus, a 93, exhibited hard starting, lumpy idle, hesitation off of idle, and I finally replaced 3 fuel injectors which fixed it.

 

[punisher]

"Downstream HO2S Sensors not tested"- doesn't mean anything. You have to do a specific OBDII drive cycle to get through a complete cat check. I have put 30-40 miles on a vehicle without getting that code cleared on some problem children, just the way it goes. It won't effect drivability.

Rough idle- if you have access to a real scan tool with a DCL function, monitor the short term fuel trims at idle, see if they are lean. Lean would indicate a vac leak, or a leak between the MAF and the throttle body, ck that intake tube from the airbox to the TB, ck PCV as well.

Conversely, if you have a bad MAF sensor, look for rich trims at idle, moving to leaner trims when the engine is loaded.

Ck your throttle body for sludge. It will mainly effect idle smoothness. With a proper scan tool you can look at your ISC % and see how much the PCM has to open it to control idle. High % = low throttle airflow. Most new throttle bodies since the mid 90s have a sludge resistant coating and are pretty maintenance free. Excessive blowby will trash/sludge any throttle body though.

Improper injector flow will cause misses/engine roughness, more notable at idle. It can be anything from low flow to a bad spray pattern. If you have an injector miss, or an ignition miss bad enough to feel sometimes you will get a P030X code which will narrow down the offending cylinder.

An EGR will more than likely set a code for "excessive EGR flow" if there is a problem with flow at idle. Those particular EGR valves are pretty robust, we never encountered real problems with them. Apply vacuum to the valve while the engine is idleing and see what happens, let the vac off suddenly to snap the valve closed to see if it makes any difference.

In a perfect world the shop you have look at it will be able to do a power balance test, injector flow test as well as have a data capability so you can see what the PCM sees. Once you have that info it really is easy to fix. The problem is throwing out guesses without the right/enough info. Sometimes you luck out, sometimes you don't. Just having the trouble codes is usually not enough to fix an actual driveability problem in many cases.

Non engine issues- check the RF motor mount. The mounts on earlier 3.0s had a tendency to have the upper bolt vibrate out, hard to catch unless you are looking right at it. The problem should have been fixed by '98, but checking it was a habit I got into.

EDIT: You are lucky to have that Vulcan vs the Duratec. Lot less problems in the long run. Mileage on the hiway at around 70mph should be in the neighborhood of 28-30 mpg.

 

[PowerPeeCee]

I've got (and honestly, wish I didn't) a 1998 Ford Taurus SE, 160,000 Miles, Vulcan (pushrod) Engine (it has the MaD VulCan PoWaH!!!!1111oneone blah blah etc etc, google it if you don't get the joke)

I have no DTCs at present, the idle is awful from the get-go, I don't think it's the HO2S Sensors because They wouldn't b0rk up the Idle immediately upon starting the engine from cold, I don't think.

The reason I mention the oxygen sensors is that I got my friend, who's a manager at a transmission shop (good to have a friend who is the manager at a transmission shop when one drives a Ford Taurus

) and I got him to have one of his techs probe the car with this super expensive OBD-II Scan tool they have and it came up with something like "Downstream HO2S Sensors not tested", I know the sensors were hot enough because I had to drive like 15 miles to the shop, and it sat for maybe 10 minutes before they tested it.

I've taken off the IAC Motor and given it a good blasting with CRC Lectra Clean, made sure the plug wires and the plugs are decent (changed both within last 6 months, put about 4k on the car since then) Plugs are Autolite platinum, wires are Duralast from AutoZone (scold me, I should know better)

I tried to locate any leaks in any of the 5234423 little vacuum lines that are strewn about the engine compartment, and I've had no luck.

Would a slightly stuck open (doesn't close all the way) EGR Valve cause these symptoms?, it's bumpy and grumpy through all speeds and gears, although it drives pretty much normally, except for the instability.

I'm still getting the same mediocre 20-ish MPG i've always gotten.

I've got the heater hose bypass kit installed, per the TSB (bridges the heater core lines so if the heater core plugs up the head towards the firewall will stil get coolant flow) and the temp gauge always reads 2/5ths between cold and hot,

I put a new water pump on it recently (the bearings were making noise, I replaced it before the impeller could start to scratch the inside of the housing) so I know I have decent coolant flow, and the amount of green death in the little pressure tank remains the same. I don't think I killed a head gasket, or an exhaust valve, the exhaust is normal, doesn't smell abnormal (yeah, I smelt my exhaust, if only momentarily, very ozoney) and the exhaust seems to have the right "flow" about it.

So what I'm asking here is why won't the

thing work right. What curses or incantations must I perform to make my F.O.R.D. behave again?

I thought about asking the guys at Tauruscarclub.com, but they have consistently failed to provied anything like an intelligible and/or useful response to any of my queries.

 

[oilboy123]

Vulcans are not glamorous, but at least they are easy to work on. They are durable and cheap to fix or replace as well

Before my warranty ran out I had the 3rd dealer look at the rough idle on my 98 Vulcan Taurus.
They reprogrammed the computer and it started ping out of nowhere a week later.

I have not been able to eliminate the pinging since then. I have had several shops try to find the problem to no avail. I did run auto rx and let my daughter drive it while fishing in Alaska. When I came back the pinging was gone?

The maintenance auto rx does not seem to keep the pinging at bay. I am expermenting with auto rx and the ping problem
Just a warning about the reprogram. Good luck.

 

[PowerPeeCee]

Mine's got the reprogram too.

Mebbe I should try higher octane fuel.

Ford _really_ should have put a knock sensor on this thing.

I wonder, is there a way to retrofit one onto the car?

I know there's an "Octane plug" somewhere on the wiring harness that when pulled retards the ignition timing a bit, maybe I could try yanking that and see if it helps, I can't seem to find the plug, though.

I like the low end GrRrRrunt that the Vulcan has, BTW, I wasn't making fun of it in the first post, just being facetious.

I like any engine that has cast iron block and heads, pushrods, and a timing chain.
[tim allen] auh auh auh!

[/tim allen]

 

[oilboy123]

I was told mine did not have the octane plug. I remember working at a Ford dealer in 2000-2001. The new tauruses were then coming with a knock sensor.

I was thinking about a retrofit. I just think it might be a can of worms.
I was even thinking of buying a PCM tuner to back off the timing and fatten up the mixture. In general experment to help the pinging. Mine does respond to better fuel, I'm just too cheap to do it

There is mention of the tuner at taurus car club of america. At least a while back. Let me know if you find something that works.
Gotta love Tim Allen.

 

[SHOZ]

I will tune your taurus.

 

[oilboy123]

SHOZ What do you mean? From Illinois? You have a tuner? You can loan me?

I have a close to a full clean dose of auto-rx in right now. I want to see if it gets rid of the ping. Like it did last time.

I am also driving more agressive like my daughter does. This in the hopes that the carbon gets out. We will see what happens.
I have regane in the tank as well.