97 4.0 4x4 hesitation at 55+

[Sally88]

My Ranger at highway speed for some reason loses power for split seconds. The best way to describe it is this: At 50+ mph it will hesitate a split second then be ok, then 3 seconds later it will hesitate, then ok 3 seconds hesitate etc. In neutral the engine revs just fine. Its as if the battery is being unplugged. I checked that, and that's not it. There are no loss of lights either. I also put in heet thinking it may be water in the tank. Also put in fuel injector cleaner. Any ideas?

[Sally88]

It turned out to be a mass airflow sensor. The check engine light came back on and I'm getting the catylytic convertor checked tomorrow.

[e_powers]

what is the code that accompanies the check engine light? have you tried seafoaming it to remove carbon?

[Sally88]

I spent $539 and the dumb check engine light still pops on. Nobody can figure out why. It gives an EVAP code. I have replaced the DPFE, purge solenoid, EGR valve, all the hoses in the emissions, had the catylitic converter checked, done a compression check, changed the air filter, plugs, new gas cap. It runs fine, but the dumb light comes on when I drive it hard, like when I pass a car or am in a hurry. I wish there was a way to pull a fuse so the light would go out. It is embarrasing when anyone rides with me. I also want top dollar when I trade it in. What is seafoaming?

[e_powers]

Seafoam is a product that cleans out the carbon build up in the intake system you remove the brake booster line and slowly let the engine suck it in. once a 1/3rd of the can is sucked in you kill the engine and let it sit for 20-30 minutes and crank it back up after you replaced the brake booster line clear the smoke drive it around and change the spark plugs (seafoam fouls them most times) and your engine will be officially decarboned . IT will put out ALOT of smoke. but your engine will run noticeably better after plugs are changed.

another thought crossed my mind is that carbon plugs up the egr valve passages. especially around the valve check it.

it will help alot to know the code thrown.

[Sally88]

I already changed the EGR valve. I will never buy a Ford again. Even the dealership can't figure out why the light is on and I'm getting 11 mpg. What a piece of crap.

[e_powers]

what is the code? don't call a car a piece of crap. parts do wear out. take care of your truck and it will take care of you. take your truck up auto zone, they will pull your engine codes for freeeeee. then get spark plugs and some seafoam and run that in your engine through the brake booster line. then change your plugs. i understand you changed the egr valve but there are passages that lead up to the valve and if they are blocked then the exhaust gass does not flow.

[Sally88]

I have taken it to Auto Zone more than once, same code, Evap and they can't help me. I have only had the truck for 10 months, and have put about $1300 into it to try to get the dumb light to go off. I have also pulled the gas tank and put in a new fuel pump which was $500. As far as seafoam, Auto Zone doesn't list having it. Also, where would I find the brake booster?

[e_powers]

telling me it is the evap means nothing. i meed the actual letters i e p0456 or something. brake booster is the big round thing right in front of the driver. on the firewall there should be a semi big hose coming off of it.

[e_powers]

try a differant mechanic. i never had a problem that after spending 1300 it is not fixed. there is nooooo code evap. the codes stored in computers will start with a "p" and 4 numbers after it. the code may be evap related but there is no code that says evap. and once you can spew that combination of numbers on to these boards some one may in fact tell you what you need fixed. and because of your attitude i for one hope it is a cheap and easy to fix item. because if you were not reading the codes all you can do is change expensive items to try to fix this.