Thanks. About how much did that cost you? dumb question, but is the coil part of the rotor?

$125 for the coil. The coil is to the left of the engine, located just behind the PS pump and attached to the chassis. Matt these stumbles can be caused by fuel delivery aswell. In fact, I have a big thread where I asked if it could be my coil, then went down the fuel direction only to comeback and replace the coil. It is a very easy diy so i would definately check it.
m

Thanks. I think they just replaced a fuel filter. Amazing. This stumble has been diagnosed for over a week to no avail.

After putting on Mercedes wires, they are saying the car is running worse now.

Does Steve Brotherton have any advice? It would be appreciated if available.

Believe it or not when they replaced the dirty fuel filter, it ran even worse after that. It is running pretty poor after a load and they cannot figure it out.

They are going to slap on a coil on it on Monday and see if that does anything.

They said the only thing it could be after that if the fuel pumps or the air flow meter.

the fuel pumps can be checked by checking fuel pressure. Check before the regulator and after the regulator. Check the duty cycle and eha numbers to see if it really is the AFM. That only needs the potentiometer as the mechanical part very seldom breaks. These guys look like replacers not diagnosticators. I would be wary of just replacing everything as this can get very expensive they can test all this stuff. Most of it is quiet easy now that steve has taught me how.
Good luck.
m

Thanks Martin, I really appreciate your help.

They said that they checked almost everything that it could cause this. They replaced the wires, plugs, (the rotor is new). They said that they checked the fuel pump pressure and it was borderline OK, but was unsure if the fuel "volume" was acceptable - they were to recheck today. Thay also checked the head pressure of the cylinders and replaced the spark plugs after they said one was bad. They thought that there was a misfire at number 2 before they replaced all the plugs because when they witheld fuel from the fuel injectors from #2, nothing happened.

They checked the fuel disitrbutor and do not think it is that. Also checked the EHA.

They said that the only thing that it could be is the coil or the Air Flow Meter, but are thinking that these symptoms that it is not the AFM, but the coil. They will be on a new coil this Monday and see what happens.

They are saying that will a car with 235K miles, it is hard to diagnose a problem like this. Otherwise the car runs great.

Now they are saying that it runs a little better than before on idle, but worse when accelerating. Only if you ease on the pedal is it OK. :mad:

By the way Martin, I read your earlier post and link on when Steve helped you out with the coil situation more thoroughly. I am hoping my problem is the coil as well. One thing that is interesting is that the car does not stumble at idle or acceleration after sitting over the weekend for the first 5 miles (when car is really cold). The tech said that the coil could worsen when the the car heats up and could explain the stumble after that. In any event, the car's temp is affecting something, whether fuel or electrically related.

they can test the temp for the ciruit very easily. plus a new one is only 17 bucks. But that should always be the case from cold, not just after sitting.
m

Thanks.

Update:

They checked the duty cycle (lambda) and is good. Checked the EHA and is good.

Checked the fuel pump pressures before and after regulator and is good (but he says the fuel volume is still not to his standard.)???

He is first going to put another fuel pump to see if it makes a difference and then a new coil. Will put back old one if does not make a difference.

They scope is down so cannot test coil. But reason why replacing is because nothing is jumping out that it is bad or not but sometime is problem (like martin's coil).

Matt, I would go with the coil sure does sound familiar.
m

Thanks. Will know more Monday.

Can you swap coils with a good known one for testing?

Yes, will swap on Monday first thing.

They put on two new fuel pumps - got a tiny bit better. They put on a new coil and it got worse so they are putting the old coil back on.

They said that it now idles fine, but when one accelerates it could be fine or it stumbles like there is a "dead spot". They said that the only thing left that it could be is the air flow meter, which is $1,000.

I am going to hopefully check on it tonight myself.