Hello out there, MY brother's son's van has #4 cyl misfire rough idle,but drives great.

test spark plug wires / clean spark plug / clean map senor/ sprayed cleaner to clean injectors.changed cap rotor /changed some spark wires ,just to see what happens.

same thing. Now I'm going to change the two oxygen sensors on each exhaust pipe.

I removed cat for now too!

After the run / if same thing ,changing pick up coil / or going to remove the whole dist and going to test. it. volt and spark.. also check for throttle moving play.injector I'm going to remove and also going to test,just to see.

I did this to my 1989 chev van ,and after ran very good until it got total.change coil and tbi senor and clean map senor.

Mine has been doing the same thing at 200,000 miles. Auto Zone read the Service Engine codes. Either plugs and wires, or vacuum leak OR if not that then the injectors or high/low fuel pressure. We changed plugs and wires and also while doing that found some pretty bad split vacuum lines. WE replaced those and so far I am back up to 18mpg in town and she is running better however with this Chevy you never know. We have thought we have fixed things before and it goes good for a while and then suddenly there it is again.

I have a 1999 Astro van. the problem I'm having is the same problem everybody i talk to has. you can be going down the road and it will start jerking like a misfire. i have pulled the code its a p-300. that is a multiple cylinder misfire. cant seem to fix it. my friend had the 1999 year model. and it was doing the same thing at 60,000 miles. changed everything under the hood. still the same thing, down the road a ways, it will take the notion to start misfiring. i think with all i have read about the 1999 and 2000, there should be a recall. can anyone give me some more advice? the problem is getting worse. starting to do it more often. think it may quit on me. is it a lemon or not. have talked to several other people that is having the same problem

First in 2004 I wet to the dealer they replaced the harnesses, plugs, rotor and did a tune up $400.00. I think they took a wild guess what was wrong. It worked for a year 4 days after that year was up march of 2005 about 6000 miles later it happened again. this time I went to monro muffler they said the catalytic converter is clogged so they replaced this and the wires, spark plugs, rotor and did a tune up $2600.00. Now I went back last week January 2006 and had the same problem, misfire, on the highway I get it up to speed let of the gas a little and it jerks around I get back on the gas it runs better. Now I went back today and they told me it could be the head gasket they discovered that the coolant was low and it may seeping into the cylinders causing the misfire. But why is it doing it only between January and April and not in the summer for 3 years now. I got that feeling that I am being ripped off.