Engine Bucking, Acceleration Issues

92 PA Base
141,000 mls

Whenever I have to drive for more than 50 - 75 miles or for one hour at a constant speed, the engine causes the car to buck and loose acceleration. When I press the gas pedal down to the floor, the rpm's stay at zero or when I lightly press the gas pedal, it would accelerate but with noticeable hesitation and difficulty. I go from maintaining speeds of 70 miles down to 40 miles. It also feels like no fuel is getting to the engine. This causes me to pull over for a few minutes, shut the engine off, and then its okay to drive for a few more miles.

I replaced the fuel filter and the MAF sensor. When I changed the MAF, I noticed that the bottom portion of the old one where the little wires are, was broken. I really thought that was the issue but when I replaced it, it started doing the same thing.

What should I check or replace next?

Thanks in advance.

Have the fuel pressures been checked? A good code scanner with live data capability can be very helpful on this. Especially in the hands of an experienced technician.

No, fuel pressures have not been checked. I'll look into it.

Thanks

If fuel pressure isok, has the vehicle been scanned for codes? P0300 has not been set?

When the car acts up, pull over safely....

Now from a dead stop, lay into the accelerator pedal........does the car bog down, max out at 3000 rpms, and not shift?

Stop again.....now from a dead stop, very lightly accelerate.....if the car slowly accelerates and shifts gears, and gets up to speed, you could have a plugged or partially plugged cat.....

Tech II... Or you could have a stuck "Enter" button on yer keyboard!

@ Tech II

Car has not been scanned for codes neither is generating any codes.

What is P0300?

Yes, the car bogs down when I lay into the accelerator from a dead stop. Yes, to the 3000 rpms and gear shifting.

Yes to the light acceleration and slowly speeding up with minor bogging, hesitation and spurting. Yes it slowly gets up to speed and shifts gears.

You have described exactly everything that is going on.

How do techs check for plugged catalytic converters and how much does it normally cost?

Thanks

@ DeltaP,

Where's the keyboard located?

I was attempting humor towards Tech II. His response post: "If fuel pressure isok..." showed up 3 times in a row! Other than that I think he's given you excellent advice.
Cat converters can be $$ so get multiple estimates. Usually one can temporarily remove the forward O2 sensor or unbolt the front of the cat if not welded in and run the engine under same conditions to see a marked performance improvement. But there should be a stored code,(s). Something in the P0400's I think.

I don't know what happened...said I had to wait 30 seconds to post.......must have hit it several times....then I walked away and came back and saw the multiple posts.....



Car has not been scanned for codes neither is generating any codes.
Should scan it...

What is P0300?
Misfire code....

Yes, the car bogs down when I lay into the accelerator from a dead stop. Yes, to the 3000 rpms and gear shifting.

Yes to the light acceleration and slowly speeding up with minor bogging, hesitation and spurting. Yes it slowly gets up to speed and shifts gears.

You have described exactly everything that is going on.
That is my simple test for a clogged converter.....

How do techs check for plugged catalytic converters and how much does it normally cost?
Just like DeltaP suggested....remove the pre cat O2 sensor(this will be loud).....then lay into it....if power returns, it's the cat......his other suggestion of loosening the exhaust pipe from the exhaust manifold, and creating a gap, is another way of doing it, but it's harder and a bolt/stud might snap......

As DeltaP said, get estimates......but look at the size of your cat.....do not get a "mini" version of it......

Is there a tool or device that I can use to check the spark plug is firing? Also, what method/steps should I use to check whether the spark plug is firing or is it creating a spark? Please correct me at will, I'm no mechanic.

Is it right for a shop to charge me a 'computer diagnostic' fee if they aren't using a computer or scope to diagnose? I don't mind paying a diagnostic fee but don't tell me you're going to check my car with this $5000 sophisticated computer when you don't have one in your shop or if you're only using a am or volt meter.

Please tell me what you think.

Thanks

Well, as soon as any "garage" hooks up a scan tool to your vehicle, it becomes a diagnostic fee.....if you just are checking for codes, places like Autozone will do it for free.....

There are various spark plug testers on the market.....

There are various spark plug testers on the market.....
-----------------------------------------------------------------------------------
They sell them there also.

I had the exact same issue, but replacing my ICM seemed to fix it