Newbee

[jaysmgf]

Hello to all,

Just bought a 1997 2.3 with 143500 miles and on my first long run I noticed that the engine revs pulsate. What I mean is holding a steady speed say at 60mpm it runs normal then drops a little then goes back up again. This happens at speeds above 40mpm. I have added some injector cleaner and it does not seem to help

I intend to change the plugs ,air filter, and have already changed the oil and filter
Any advise will be helpful and where to start

Jay

 

[RonD]

I would give all the vacuum hoses a check, a few open only at higher rpm so if they were cracked you would notice that only when driving, not at idle.

Not sure if EGR valve or system would change RPM, but it could, EGR is only used under load, so if it's vacuum or sensor was acting up it could be opening and closing when it should be steady.

Most auto parts stores will read the OBDII codes for free now, I would see if there are any codes listed, the CEL(check engine light) doesn't come on with all codes, minor inconsistencies will set a code but not activate CEL.
This might give a clue to the problem.

 

[Surrey]

Does it do this when revving the engine while stopped, or strictly when moving at 40mph+?

Have you checked to see how dirty your old air filter is? You can always try running without a filter for a few minutes, see if that changes anything. Air filters are typically not the problem, but its an easy place to start.

definitely check all your vacuum hoses.
Might also want to change your fuel filter.

 

[jaysmgf]

jaysmgf

Thanks guys for the info. Will start checking all hoses

I will call and see if Auto Zone will run a check on the
old beast
I intend to change all filters air,fuel and also the plugs and
plug wires

Jay.