ok, so lately my v6 camaro has been acting up..when the temp on the engine starts to go up a little.. is when the problem starts.... when i go to give it gas it misfires...(poft) sounds come from the exhaust even if i just pres the gas gently it will do it ocasionaly..... sometimes it will be worst then other times.. and sometimes it wont even do it at all.. when i leave to work in the morning and its cold engine runs perfect.. no problems at all.?..
i have changed the coil.. and put new plugs... checked for vaccum leaks.... it has a 1yr old distributer... newer wires.. i cleaned out the MAF sensor... tested the EGR...filters are clean..... what can be causing this??

 

try replacing the temp sensor on the intake manifold(in the front by the coolant port)...back when i had running problems with my car i was having false readings from the coolant temp sensor. The computer uses that data and changes the fuel input. I think its like $30 for the sensor or something. I have an extra sensor laying around if you were close id have you drop by and we could try it out. Id say try it...if not it might be something else fuel related. Usually a backfire is either fuel or spark related. Seeing as you have mostly new ignition i would guess its fuel related.

 

thanks for the response....
i think you might be right it sounds like it could be that... something fuel related i doubt because it only starts to do it when its hot and ... even if its hot it will idle fine... i will try that sensor...

 

i changed the sensor and it made no difference... this is really strange problem because it will misfire worst as the temp gets higher.. help!!

 

Is it timed correctly? Mine started doing that when the dizzy hold down decided to shake itself free.

 

what he said, check the basic first.
have you checked to see if its thrown a code ?

 

Dont throw parts at it, thats just a waste of money..... as you just found. How did you "test" the EGR? How does it run/idle? smooth, stumble, etc?

 

When you figure this problem out let me know. I was having the same problem, thought I fixed it but now its back.

After the missing when you press the gas does it eventually start running better at speed? I have mine narrowed down to running really rich when at idle and it bogs down and misses horribly when i hit the gas but then clears up about 50ft after.

 

that last post sonds kinda like a MAF gone or going bad. Both of you sould un hook the MAF and see if the car runs better. If it does i would get a new one. Also while driving with it un hooked you may stall out when stoped and it may sputter a little while excelerating but if it makes a big diferense go for it. you see when you un hook it the ecu thinks its completly toast. So it has a pre determind memory to make the car run ok with out a sensor in some cases. It may not really be a fuel problem persay but the computer telling to give to much or to little fuel. And dont forget the very basics like the fuel filter i would check that also the O2 sensor if you have the money i would change it any way unless resently changed> It should be changed anually. Also you sould run fuel injector cleaner. Im a strong beleaver in addatives and dont get the cheep stuff either get lucus or marvel. Gumout is ok but you could do better.

 

the strange thing is no SES light.. i am sure if it was the o2 sensor it would come on.. and to drdave88 on my haynes repair manual it says to check the egr by pressing up on the diaphragm manually if its stuck its bad and if its takes too much effort to push up is bad.......... this problem is really starnge because it will idle rough only when the temp is high 220.... and the tach will start pulsating.... if i let the car cool down for about 2 hrs.. it will idle fine and i drive it it will run perfect untill the temp comes up it will start misfiring idleing rough and the tach will start pulsating...WTF... this is not a constant problem.. so i dont know what it could be....

 

no it will miss when i hit the gas all the time but only when its hot.. if the temp outside is cool and the car is running cool it will not miss it will run perfect

 

fuel filter is new.... o2 sensor was bad it would give SES light immediately... and yes i have used lucas fuel additive and its the same.......

 

timing i dont think is the isssue because if it was the timing it would be constant which is not idles fine and runs fine when the temp is cold......... the higher the temp goes the more it will misfire and idle rough and the tach will start pulsating

 

ohm the injectors and see if you have one going bad.

 

Ah, you're right, it couldn't be a timing issue. Someone suggested to me rust in the gas tank, and as your driving it gets clogged in the FP. Not sure how much truth that statement has but my next step was to drop the gas tank and give it a scrub.