1994 Mazda 626 2.5L rough acceleration

[balut]

Hi: I just replaced fuel filter, spark plugs and spark plug cables
because the car is rough during acceleration. After doing these things the car is still rough under acceleration. Any help in trouble shooting is appreciated.
George

 

[Cup of Joe]

Be more specific rough how? And how bad is it? Could still be allot of things, any check engine lights or stored codes? TPS, MAP or MAF will make a car nearly undriveable. TPS would be very common for a car this old, but you should have a code stored check the codes.

 

[bdcardinal]

did you use OEM parts?

 

[chrome]

It could be a variety of reasons, but since you have covered the basics with new plugs and wires, I would venture to suspect a vacuum leak, or possibly a bad air flow sensor. You will need to pull the codes from the diagnostic plug using an LED and resistor plugged into the B+ and FEN terminals, and ground the TEN pin. Turn on the ignition to on, and watch the LED for the codes.

 

[balut]

I'll go to Autozone if they could help me pull the codes.
Keep you guys posted.

 

[RTexasF]

That engine has somewhere in the neighborhood of 50 vacuum lines. That is a good place to start looking. I went through that with my '96 2.5 V-6 and replaced them all....problem solved.

 

[chrome]

I am not sure if AZ will be able to pull the codes, as your car is pre-OBD2.

 

[mechtech2]

Compression, ignition, and fuel delivery.
Check your compression - you may have a bad cylinder from worn rings or a leaky valve.
Your coil may be bad - they can crack and leak, or otherwise puke.
Is an injector laying down and is partially plugged ? This will make one cylinder different from the rest. The fuel pump may be weak.
And of course, your PCV and vacuum lines have to be perfect -each end. Also the intake.
This list is only partial, but is a good place to start.
Good luck.

 

[Tosh]

How are MPGs? If it's knocking, how does it run on a higher octane gas? Did the problem show up suddenly? If not, I would suspect the usual gunk build-up on injectors and combustion chambers and start using FP60 regularly with every tank. But don't expect improvement for a few months.

 

[balut]

Thanks fellows for the reply. I went to the my auto mechanic and he said it's the distributor. The distributor was replaced with a used one before, but no rough acceleration as the symptoms. I am stump.

 

[rat]

I did not see where you changed the cap and rotor, I would change those first just to make sure as we had alot of those issues at the Mazda dealer I worked at years ago.

 

[wavinwayne]

Check your air intake hose for cracks on the bottom. I had a '90 Mazda MX-6 with the same symptoms. Cracked air intake hose (on the bottom of the hose).