Ford 2005 Freestar Hesitation

During acceleration my freestar will hesitate or stumble. I was entering a freeway and when I accelerated the car started bucking I thought there goes the transmission and then there was a pop,pop and the car took off like nothing was wrong. Now when I’m doing 45 mph and accelerate the car stumbles and then picks up speed. Twice when I accelerated the car shut down. As soon as I stopped I turned the key and it started right up.?

Most likely “leaning out” No MIL light? Could be fuel delivery / injector. I would be curious how the MAF would test (grams/sec.). They can give problems. Have someone look at the live data.

Had car in garage today, they ran all sort of test today and the only thing that came back as a problem was Airflow? They road tested the car and it hesitated, back fired and stall out and they had no idea why?

I think maybe you need a new garage. This should have been driven while connected to a scantool. Even if it isn’t routine to test drive this way, certainly another drive after this event would be in order.

Or -perhaps are you saying that they gave you a diagnosis and fixed it? Its hard to tell. The “airflow” reference was likely to a mass airflow sensor (MAF). Its in your air intake tract and is crucial to engine management. If it is not working properly, either because it failed, its wiring has a problem, or is dirty this could certainly cause the symptoms you report.

So did the shop actually do anything? Is the stumble gone? If not, then report as much as you can about their diagnostic attempts including computer error codes (format: P1234) if any.

They did drive with a scantool and when they gave the van a lot of gas the van stalled out and thats when they got the airflow on the sensor. Diagnostic showed no computer codes. They did nothing but give me an address to another repair shop that they said could help me. Still have the same problems.

Go to an auto parts store, buy a can of MAF Cleaner. Your MAF is in your intake tract between the air filter and where it attaches to the engine (at the throttle body). Pull that off to see what you have to do to get close enough to the MAF to spray it down well with the MAF cleaner. Button it all back up and see what happens.

(Maybe you need a new air filter while you’re at it).

Brought the MAF cleaner sprayed the sensor and replaced the air filter. Van seems to have more pick up but problem still exists.

Some of my relatives had a problem like this happen to their Windstar. The alternator was found to be causing the trouble. I didn’t work on it but I assume it was generating excessive electrical noise at times which could cause the ECU trouble running the engine properly. Possibly dirty slip rings inside the alternator are the cause.

Van was repaired today by Ford Dealer. It needed a Coil Pak.

These are not fun problems to run down. I would be happ if I were you.