This problem has stumped EVERYONE!

The car runs perfectly fine and boosts 12-13lbs when its cold.
But when its warm - after 10-20 minutes of driving, the following problem occurs:

When the car is below 2000 RPMs, and if I give it a lot of throttle, it will stumble and fall flat on its face pretty much. It will slowly accelerate if I give it very light throttle.
But climbing up hills, it is EXTREMELY slow -
unless I am above 2000 rpms.
If I'm above 2000 RPM's, it still stumbles, but doesn't fall flat on its face. The tach bounces as well.

I brought it to my friend who works at ford, and we pulled codes 212 and 216.
I was hoping to narrow this problem down so I don't go out and throw down more hundreds on parts on this car that I don't necessarily need.
I've replaced:
-DIS (other unrelated problem fixed by this)
-Spark plugs and wires
-Tried an ignition coil with the faulty DIS, determined the ignition coil wasn't the problem at the time - so I returned the ignition coil.
-I replaced the camshaft sensor a couple months ago, but the harness clip is broken.
we checked the fuel pressure, it was fine

sounds like fuel pump to me . mine acted up for a year mostly when warm after 20 to 30 minutes sometimes it would be fine till i came to an exit or stop sign when i would lift off the gas it would die , then restart . finally after i tried everything the fuel pump fixed it

What do you mean by "the tach bounces"?

If it is reading incorrectly when it is running poorly, I'd try another DIS module.

wes-harrison said:

we checked the fuel pressure, it was fine

Click to expand...

you checked at idle, or going down the street? You need to check fuel pressure when you experience the loss of power.

Bad DIS and or MAF.

SWS

Several times I've had DIS problems, the car would run fine when cold/cool, but once the engine warmed up, the DIS would start acting up and having symptoms exactly as you described.

A problem gets even harder to figure out when you've replaced a part with a bad one!

Probably not the ect sensor but you never know. The DIS module is prone to heat issues. (Not sure how you could test DIS for heat) Perhaps get the car up to operating tempature, shut the car off pull the DIS module. Wrap a bag of ice around the module for a few minutes. Make sure you still have plenty of thermal compound on it before placing it back on. Once on the car should still be around operating tempature; go for a test drive and see the problem is gone. It wont take long for the DIS to heat back up, probably have enough time to do a quick test.

Good luck

I vote for MAF....if the fuel pressure is OK....

Check to see if any of the plug wires are shorting on the header primaries.

BAP can mess with your timing too. But I would recheck the plugs, wires, and DIS. It sounds like an ignition problem.

Sounds like either the IAT or the ECT. If your friend at ford had a descent scan tool that can do datalogging, get the car warm, go for a drive, and hit the record button. My matco determinator has that ability and it is a life saver. You should be able to log all sensor values. Beats replacing random parts and wasting money. Good luck though.

flynbrd> Not sure how you could test DIS for heat

Try a digital (non-contact/laser target) thermometer...less than $25 lately. Very handy...great tool, everyone should have


Or use an IR camera as in the shot I took below (attachment). Another excellent tool and less than $5k these days.

You can see the DIS isn't all that hot in this case - the engine had been running at idle for approx 45 minutes (target Sp1=189.5º). I've seen the DIS get up to 145º F after a run down the freeway, while the pad/bracket was hotter at 175º - that's the main source - the compound is to help reduce heat rising up/soaking from there.

As pointed out, if you suspect a component and decide to replace it, replace it with new. Also, don't ignore the many grounds involved. Find/see the SC 'component locator' pdf for the ground bundles on the header panel, check the multiple ground straps on the engine and replace if corroded/old.

Check/clean/tighten every connector you can see. Make sure the battery cables are clean and tight at the battery and confirm at least +12.5v when running.

Check the ignition switch for integrity (the one down on the side of the column) and focus on eliminating those codes.

Stick with it. It might take months and hundreds of $$ worth of parts, but you'll wrestle it to the pavement eventually. Keep your receipts and mark any spares so you know which ones are duds to throw out when done.

I think you car is new you should drive it slow till 1 or 2 months after some time its part will work properly. Keep it in the service but do not give overload. Regular servicing is must.

Cocktail chiller

My uncle was a TV repairman. He use to spray cocktail chiller on parts to see if they were thermally open when hot. Would need to have enough liquid flashing off to vapor to remove enough heat from the part. Of course, make sure the liquid is non-flammable.
Good luck
-Dave

thanks for all the replies! glad i finally joined the forum aha...my hg actually just went tho so thats gunna be a job and a half

ok,

1. Does the vehicle run fine in open loop up until it reaches closed loop?

2. If it runs fine till it reaches operating temperature and enters closed loop operation i would go right for the pre catalyst Oxygen sensor, as this sensor is ignored up until the point that the vehicle enters closed loop operation. seen this all too many times

gmctech said:

ok,

1. Does the vehicle run fine in open loop up until it reaches closed loop?

2. If it runs fine till it reaches operating temperature and enters closed loop operation i would go right for the pre catalyst Oxygen sensor, as this sensor is ignored up until the point that the vehicle enters closed loop operation. seen this all too many times

Click to expand...

YUP thats exactly how my car was running. had no check engine lamp on or flashing but had no power and would stall and die at strange times wouldnt accelerate only when motor was in closed loop.

I have a thread on here that showed my scan tool and the o2 sensors were basicly not doing anything usefull. thus the only happening in closed loop scenerio. if the car had a shorted wire, bad module (dis) ect i would suspect it would do it all the time (maybee the dis is getting hot as some have said) but if only when car is warm and in closed loop anything that meeters or changes the air fuel ratio would be at fault I would suspect.

mine was both 02 sensors, changed them and wow what a different car.

Another possibility could be your fuel filter, I had a old one that had also been partialy crushed and the car would run fine until I pulled all the fuel from the filter to the engine, then I had to wait for everything forward of the filter to get back up to pressure. Car would be a dog off the start after a few minutes of driving but would be decent in medium/high rpms

$10 at advanced auto