Hesitation on Highway

I have a problem with my 1998 venture, had diagnostic ran and they told me needed new plugs and wires. was coming up with multiple cylinders misfiring. had new plugs and wires put on, and still same problem. SES light still on, but sometimes it goes off and runs fine and some times it runs rough, at idle it runs rough and at speeds around 50-60 mph it misses. I have ran 2 bottles of seafoam in it and I took it back to the shop and they suggested doing a fuel injection cleaning service. They checked the pressure at I believe around 10, (not sure) but found no problem, but stated it was hard to check at high speeds. If it was a fuel filter wouldnt a code come up for that?? also how do you replace the air filter,and fuel filter?? I know where the fuel filter is located, but not sure how or where the air filter is. On the fuel filter, how do you release the pressure? thanks so much for any help...

I have a problem with my 1998 venture, had diagnostic ran and they told me needed new plugs and wires. was coming up with multiple cylinders misfiring. had new plugs and wires put on, and still same problem. SES light still on, but sometimes it goes off and runs fine and some times it runs rough, at idle it runs rough and at speeds around 50-60 mph it misses. I have ran 2 bottles of seafoam in it and I took it back to the shop and they suggested doing a fuel injection cleaning service. They checked the pressure at I believe around 10, (not sure) but found no problem, but stated it was hard to check at high speeds. If it was a fuel filter wouldnt a code come up for that?? also how do you replace the air filter,and fuel filter?? I know where the fuel filter is located, but not sure how or where the air filter is. On the fuel filter, how do you release the pressure? thanks so much for any help...


Okay, I chaned the air filter,and purchased a new fuel filter today, I am going to have my husband put it in this weekend. I did have the SES light checked again, and it came up with PO306, which is the 6th cylinder. The shop said they checked every thing out, the coil pack, pressure test, and believe it is a clogged fuel injector. If it was an intake gasket, wouldnt there be more then one cylinder misfiring?? it has a rebuilt motor, with 20,000 miles on it. surely they put a new intake gasket on it right. any body know what else it could be?? it seems to be ideling better since I changed the air filter, it was clogged, but still misses at high speeds. thanks so much, as I am stumped!!