Still feels like it will stall...

On the start it sometimes takes a while to start and then when it finally does it feels like it wants to stall out. I've changed the plugs and the fuel filter, any ideas anyone? Please help, thanks...

Lee

I don't know your year or model, but I think you've probably got a late nineties with a 4.0 SOHC? If so, check your IAC valve. It's under your splash shield and seems to give a lot of headaches this time of year. Usually we just replace them and if that doesn't work proceed with normal diagnosis.

It's a 1992 so you still think the IAC valve?

I have a similar problem with a 97 4.0 SOHC 110k. feels like it wants to stall going from reverse to drive. as well it shudders every few seconds when its idling. idle is usually at about 500 which seems a little low. I've heard that the MAF can cause a similar shudder as a result of runnign rich or lean. i thought the o2 sensor was to prevent rich or lean mixtures. how could i know which it is and what would i expect to pay for a new mass air sensor and idle air control valve? the MAF's seem to range from about $50 to $500.

thanks
c

Wow, I really don't know...all I know is that it's 15 degrees right now and this stupid thing won't start. I'm almost fed up with this car and would very much like to drive it off a short pier...but I've got too much money invested in it and would feel like a dummy if I did that...so nonetheless I think it's the cold that's doing it. I turn the key and *click* then nothing. NOT the battery, I've got a personal charger and it's not turning over. Don't know what it is...

I have a 1999 Explorer XLS 4.0 SOHC (61000 miles). It has been idling rough and occasionally stalling at a stop light. I replaced the throttle-air by-pass valve two weeks ago. It still acts up, and today the check engine light came on. I took it to Auto-Zone for diagnostics check. I was told "running lean on banks 1 & 2. O2 sensor failure- banks 1 & 2." I'm gonna try replacing those this weekend to see.

Ok, but what does that mean???

If you can, let me know how it goes. I havn't gone under the exhaust yet to locate the 02 sensors though, so if you run into any problems or have any tips they'd be much appreciated. I understand my 97 has 2 sensors. sounds like your 99 has 2 as well. i don't anticipate they'll be too hard to get at. it hit -20 here yesterday so i'll be waiting for it to warm up a little before i do anything else to the vehicle.

c

I'm not sure on the 92, but on the 99, DO NOT replace both O2 sensors...you'll be sadly disappointed. First off, O2 sensors will not cause a vehicle to run rough. Second, if both O2 sesors say lean, maybe the vehicle is running lean? Most parts stores and a surprising number of shops don't understand this and will just sell you sensors. On the 99 4.0, there is a TSB for intake air leaks and a kit with revised O-rings. If you're fairly experienced, then they shouldn't take more than a few hours to install. Just make sure you spray the EGR tube with a penatrant before reinstalling, otherwise you end up beating the manifold with a hammer.

Lee81, You say it's not the battery. Do yourself a favor and borrow one from another vehicle for one try. If it starts with the replacement you'll know it's the battery. If your battery is shorting internally, a charger will do the same thing.

well I'll try that, but I just replaced the IAC valve and nothing, still running rough. If not that batt, or the IAC then what?

Not sure where I came up with the battery thing. I have a bad memory! Was there another thread posted by lee81 that I tried tp help with? Because after reading this initial post I realize it probably has nothing to do with a battery! Sorry if I mislead.

Well here's what's going on with this thing...I start it up, it idles really rough, the engine rocks back and forth like something is loose in there, and then there's is a strong exhaust smell, usually there's a little smell but never in the cab, now I smell it in the cab too. At around 35-40 mph the whole car vibrates and continues to do so, doesn't ever stop unless I take my foot off the accelerator. Ummm, let's see what else is wrong with this thing...there was a problem that was fixed with the bearing, the right front tire's bearings were replaced, I need new rotors on there (and new breaks but duh on that one) and that's really it I think. I've changed the spark plugs, fuel filter, and the IAC valve, what now? Please advise...

Lee81:

Look at the intake manifold on the driver side near the firewall. Look for where 4 vacuum lines come together to a common connector. I suspect that one or more of the vac. lines are disconnected. Some of the ports are not used and they can be capped. Also if you see oil inside the vac. lines that would be caused by the vac. modulator at the trans. and tranny fluid is being sucked up the tube. The fluid will cause swelling of the vac. lines at the intake port connections and the vac. lines will come off. BTW, did the vehicle backfired at some point and then the vehicle ran rough after that? If yes, it's probably the vac. lines I mentioned. Let us know what you come up with.

Catalytic converter blocked? Follow above ideas first. I'm just guessing

Ok, well I haven't been able to really get this thing to a mechanic nor have I been able to really look at it myself. Basically what I've noticed is that there is a very gaseous smell emitting from the exhaust with black smoke. There are layers upon layers of soot, or black stuff on the ground from my exhaust. What on earth can it be? I also fill up on gas on Monday, have to refill on Wednesday and then again on Friday, just from going to college and work afterwards and I've always only had to fill up once a week, not 3 times in a week. What could cause the gas smell and the black soot?