SeVeReDiStOrTiOn

When you cleaned it you removed the throttle body and then cleaned it right? That's the only way to get it really clean. It's just 4 bolts and undoing the wire harness...the gasket is reusable. I'd change the fuel filter also because it's probably the stocker.

Have you noticed if the cooling fans are coming on? The temp gauge is just a dummy gauge that'll show an overheat condition right before going into limp mode. If you're getting to the borderline of that temp it would run like crap and might not show on the gauge. Also check radiator for any blockage from debris...like a bag or whatever. Your fuel pump could also be having issues with the heat lowering the psi when hot. But then again you'd probably have this issue across the rpm's. Keep at least 1/4 tank of fuel in the tank to help cool the pump just in case...so think of the 1/4 mark as E and refill when you get there.

tom24

Yes, I removed the throttle body alltogether. It was really easy to take off after I picked up an extension for my socket wrench The gasket seemed to be in good condition, didn't notice any hardening or anything on it. And yes, I recycled it.
Fuel filter.. hmm.. could do that. It just keeps adding up on the pile of things to change on my own expense, while the car is still under warranty. Just infuriates me that the dealer pretty much refused to do anything to the car until I get a CEL light lit up.

Haven't really paid attention to the fans really .. because this issue is there from the very moment I start the car to the moment I turn the engine off. Well, actually, the hesitation is not there during the first 30 seconds or so when the engine is idling on higher revs and if I start driving during that time. (closed loop/open loop?! not sure )

So, engine warming up seems to have zero effect on the behavior, it stays the same whether the engine is cold or warm. For the issue to come up it looks like the ambient air temperature outside needs to be above ~74..76 degrees or so

SeVeReDiStOrTiOn

Yea the fuel filter is under a maintenance item like the oil/air filter.

I mentioned engine and pump temps because I thought you were talking about 100*+ ambient temps which will raise both of those...but 75* won't make a difference.

Since you don't have a programmer you won't be able to data log the IAT and MAF. Do you know anyone with a 3v GT? If it was me i'd swap out the MAF (IAT sensor is built into it) with a known good one and see what happens. I'm thinking the IAT and/or MAF is giving bad readings as the air charge warms up and becomes less dense. The throttle position sensor could also be an issue and the ambient temp is just a coincidence.

The prob is we're starting to shotgun troubleshoot and the last thing you want to do is throw parts at it hoping for the best.

tom24

This was actually one of my main suspicions before, but I kinda discarded it after I cleaned the MAF/IAT. But I guess it could still be possible that the IAT is "working" so that it's not triggering a CEL -light, but only giving incorrect values..?

I guess it's possible, but if it's a coincidence, then I'm going to go buy some lottery tickets since I seem to hit it every time!

Agreed.

Tom

tom24

Just wanted to update the thread.. no breakthroughs as of yet, but there's something else I have noticed.
The fuel efficiency has changed quite a lot; it used to be around 14-16mpg during the summer, but now it's averaging at 18.5mpg and my driving habits are the same. Actually I've been trying to "floor" it more to see if I can get back to 14-16mpg but it seems I cannot..

Tom

srouxd162

Did you ever resolve this issue? I am having a similar problem and was wondering if you ever fixed yours.

tom24

Srouxd162:

No, never got it fixed.. still hesitating, seems to be a bit better the colder the outside temperature is, but it's always there. Still no Check Engine -lights or anything, after almost three years of driving with it.

I took the car to an independent service shop and they did tests to the car for two days and came up with nothing, hooked it up to computers etc.. No misfires in cylinders or anything else wrong according to them. Ford can't find anything wrong with it either.

I've changed the MAF and my mileage went up a bit but didn't resolve the issue.

One thing that I've been thinking is, perhaps the previous owned put a tune on the car and then when he sold it off just returned it to OEM -parts but did not return to the original tune..?

If you resolve yours, I'd be extremely grateful for any tips.. I've just dealt with it so far, but it's extremely annoying and embarrassing issue.. I'm embarrassed to let anyone else drive the car, they stall it immediately when they try to get going and the first comment I hear is "oh, funny how it seems to stall so easily"

-Tom

waykooljr

Seems like you'd get some sort of code if it wasn't running the stock tune without parts that went with the tune. It's possible to to have the computer flashed back to stock but there will probably be a cost involved. I had to do this for mine because I had to have a tuner repaired and my stock tune was lost. The dealership was charging $150.00 to flash it to stock but a local speed shop did it for the same price.

If you're sure it's stock, you might try hitting up the dealer you bought it from to see if they'll flash it to stock for you, it's the least they could do if they sold the car that way.

srouxd162

Tom,

My problem is fixed and it was my original concern. My issue ended up being a vacuum leak upstream from the MAF sensor. On my 3.7, there is a crankcase breather tube that runs from the driver side valve cover to the the intake past the MAF. Inside the hose where it connects there are two O-rings designed to seal the tube to the nipple it fits on. Both of the O-rings were out of position allowing air to pass by. This air was unaccounted for by the ECU and throwing off my A/F ratio. Because the MAF wasn't able to meter the air, the ECU had no idea that the A/F ratio was off and therefore did not throw a CEL. Both O-rings were warped and one was cut, so I decided to replace them. Fortunately I found that they were very very close in size to paintball gun barrel O-rings and I have a drawer full of them, literally hundreds. I used them to replace the bad rings and reinstalled the breather tube being careful to ensure the O-rings got a good seal. Once it was all buttoned back up I cheld my breath and cranked her over. Low and behold the engine ran much better. Due to the car running rough for so long, it did take a couple of drives to completely smooth out and the ECU to correct some idle parameters. I can gladly say that my engine is back to how she ran before.

Hopefully this info helps you out. Check all of your vacuum hose connections and also any other connections associated with the intake, especially upstream from the MAF. Keep the thread updated with your progress.

-Wayde

jbo

I started getting this issue in June and have been looking for a solution since. Running rough at idle, but fine when driving. I noticed it when the outside temps starting getting to about 80. I eventually ended up getting a check engine light, though. Misfire on cylinder 2. I took it to the dealership (the second time):

Low compression no 2 cylinder. Found no 2 and no 3 cylinder camshaft journal caps to be loose. Remove caps to inspect and found badly worn camshaft. Recommend long block assy. Torque cam caps to specs. Replaced valve cover gasket.

The engine's running really good right now and effectively all that was done was tighten the camshaft journal (bearing?) caps. The bill was $500+