dartlord2001

P.S.
I Have also replaced the coil with no luck.

SS70Chev

Could be a possible fuel injector(s) going bad. When 1 fuel injector is going bad, it gets too hot and will foul out, causing a miss. It can also cause other fuel injectors to foul out too, but that is some what rare. Fuel injectors can be tested w/an ohms meter. Sometimes even running a really top of the line fuel cleaner in your tank will clean things up too. I have a 1997 1/2 ton 350 Vortech and when I had this problem it was the distributor cap. It had a hair line crack in it that could only be seen under magnification. I still have the truck and it is running great. Keep me posted if you would w/what ever solves your problem.

Good luck

Ryan

firered89

i have this same problem on my 89 chevrolet. i replaced the fuel filter, fuel pump, and ran some fuel injector cleaner through a tank of gas. the problem has not improved one bit. i am going to soon replace my throttle body, and maybe that will help. if not, im going to take it to a shop.

NCHEVYHEVN

Wow you people love to throw parts at cars. I know it's hard to put them in the shop but if you honestly don't know how to diagnose the car then don't waist your money. Now you have thrown all this money into which probly most of the parts probly didn't even need to be changed and then you might even have to put it into the shop. Just doesn't seem very smart to me.

For the guy who started the thread have you even checked for vacume leak yet? Easy way is to take a spray bottle full of water and spray down the vacume lines and listen for the motor to change rpm some.

I would also check the fuel injector to see if they are spraying good. Take off the breather and hook up a timing light to one of the spark plugs and aim the light at the throttle body. You should be able to see spray the fuel injectors are putting. You should look like a mist and be very consitant and uniform. I would suggest this also to the guy above with the 89.

yekots

I have to say that sometimes you are right NCHEVYHEVN but when this happened to my truck I did go to the dealer and they could not find anything wrong. It seemed if they could not plug into the ECM and find the problem there wasn't one. Oh, and this happened at two dealerships. I fully agree with SS70CHEV about the hair line crack especially if you went back with AC Delco cap. They have had some problems with this over the years. I feel your pain on this one dartlord2001, it does not seem like much is left for you to try.

NCHEVYHEVN

Well if 2 dealerships can't figure out why an older motor is missing then well their idiots. Their are only a few things to make it miss so not sure why they couldn't figure it out.

I know their are hack techs. or well they shouldn't even be allowed to be called techs. but parts changers that have no idea what they are doing. It sucks cause it gives all the other techs. a bad name.

kcb37

The only reason I don't take things to a dealership is because I don't trust them and half the time they don't fix things the way they should. I recall NCHEVYHEVN even saying that at 2 dealerships he knows of they will not change a tranny filter. The rest of the time it is like yekots says, they won't try to fix it or just say their is nothing wrong with it.
I would much rather take it to a mechanic I know because they will fix it right and do what I ask.

NCHEVYHEVN

Yea, if your mechanic knows his stuff then definatly take it to him. When you take it to the dealership it's kinda hit or miss when finding a trusty mechanic that knows his/her stuff.

I'll admit their are complete idiots in dealerships that have no idea what's going on and they refuse to keep up on the technology. Then their are super smart guys that will treat your car better than their own.

I just see alot of times that dealerships are better at finding the harder problems because they have the training/technology at their hands unlike a smaller local shop that may not know how something works on a certain brand of vehicle.

firered89

i am steadily putting performance parts on my truck, and at the same time, hoping they will fix the problem...

i just put in my 670cfm throttle body...the problem is still there. when the truck gets hot, thats when it starts...third gear is so bumpy and misses all the time.

do you guys think it could be an oxygen sensor? it really does affect the performance of your vehicle...im sick of it, and have tried it all.

kcb37

I have never seen an oxygen sensor make anything run bad (rough/miss/ect). It's not the greatest thing to do, but they will only make them run a little rich or lean.