Evening Everyone. While driving, I can feel my car pulsing, for lack of a better term. An example is while driving at 45, you can feel the car pull, let off, pull, let off. I dont believe it is lerching from the speed that I am trying to go, but is dying and then jumping back to speed. It is very quick and barely noticable to passengers, but definitely noticable to the driver. Any help would be greatly appreciated.

Thanks in advance
Bob

Mine did that, I replaced air filter, fuel filter, PCV valve and the spark plugs. It didn't helped... So I changed the cap and rotor and it fixed the problem! i think they were originals and my car had 116 000 miles!

I am having the same problem....at a constant speed you can feel it lurch forward and then settle down. I did a search and came up with a bad possible EGR Valve, I have already done cap, rotor, plugs and wires, so I guess EGR valve is next unless someone else has a better idea ?

Mine used to do that a little bit , barely noticable. I just found 3 bad injectors ill tell ya if it helped when i change um.

This came from another site. Moderator had some good detailed info and since several of us seem to be having the same issues.....

I would visit this site's tech section to get a good idea on those systems possibly involved /w the problems you seem to be having.

Rough idle and rough running usually involves the EGR. It's possible the EGR valve is open when it shouldn't. This can be checked simply by removing the vac hose to the EGR valve and seeing if the engine runs better or worse.

Another possibility is a bad MAF sensor. This sensor lives in front of the throttlebody. Disconnect it's connector (ignition off) then start the engine. If the engine runs better /w the MAF disconnected, replace the sensor.

Remove the PVC valve /w the engine idling. Put your finger on the valve opening a few times to block off the vacuum. If you hear and feel the ball check valve smacking around, then the PVC is good and working properly.

Base timing is set by disconnect the distributer interupt connector on the passenger side of the firewall. Also disconnect the IAC connector at the throttlebody. These will prevent the idle from varying around via the ECM. The idle set screw is adjusted to set idle to about 500-550 rpm in park or neutral. Shut down the engine and reconnect the IAC and interupter connectors. You'll have to reset the IAC by restarting the engine then immediately turn it off. The ECM will reset the IAC to is physical base zero position. Otherwise, the idle rpm might be off.

Spray some carb cleaner into the throttlebody and also into the idle air passage. The IAC can get gummed up and also cause idle problems.

I'd also look for corroded grounds and wiring that looks questionable. You might have to take some of the guages out of the dash and clean the connectors /w contact cleaner as it's possible dirt might be cause some of the guage problems.

Check to see if the speedo cable is binding. The VSS (vehicle speed sensor) is a infrared tacho device that sends pulses to the ECM to tell it how fast the car is going. If this is binding up or having a problem, it could also affect vehicle performance, especially /w the automatic transmission. The site has instructions in the tech area on how to adjust the TV cable for the transmission.

Hope these ideas help...