i replaced the fuel filter and have an air filter on the way this happens wether the a/c or heater is on or off. slowly builds up then drops back down. thanks for any input.

i replaced the fuel filter and have an air filter on the way this happens wether the a/c or heater is on or off. slowly builds up then drops back down. thanks for any input.


It sounds like you have an EGR valve going bad. But there is always the possibility of having a vacuum leak. I would start there. It doesn't cost anything. There are many other culprits to this problem though. Some can be a little costly. Good Luck.

And just for good measure, if you haven't already, add a bottle of fuel injector cleaner to the fuel tank and run that 50 miles or so to see if that helps out.

-Rod

thanks I run lucas fuel treatment every couple of months but i did find a pinched vacuum line that runs from that plasic intake hose towards the firewall will see if that helps the problem

Fixing that pinched vacuum hose probably will fix your problem. Good catch.

-Rod