i have been having problems with my car lately and i cant seem to figure out what is causing this misfire/backfire im having. Im getting no codes and when the car is first started for about the first 15 minutes it will run fine.

when i take off from a stop sign the car backfires into the intake maifold and runs like its on 4 cylinders but once it gets above 3k rpms it runs just fine.. and it also will randomly misses once in awhile while im crusing on the freeway

so far i have replaced the

egr gasket
fixed vaccum leaks
new spark plugs
new wires
distirbutor cap
rotor
coil
ignition control(ICM)
TPS
i tried a new ECM and it still didnt work right

could it be the MAF sensor?

 

I'm having a similar problem. My car is bacfiring like and SOB when I give it gas and it's runnig sluggishly. Adjusted the tming yesterday, it was pretty advanced. Got it spot on and now the car idles much smoother but it's backfiring even worse than before.

 

I wanted to let people with 2.8-3.1 engine,I was having problems with my v6 just off idle when I hit the pedal it had this bad flat spot where the engine didnt respond for a second or two and then it kicked in,and when I started to come to a stop the RPM's would dip twice before I actually stopped.I replaced everything in the ignition system..and even checked timing a hundred times.I checked the timing chain ,without removing the cover.It checked okay..so just lived with it..till my water pump went out and in replacing it ,I decided to remove the timing cover.The chain has a dampner in between the crank and cam gears and that's what takes up the slack.Its not a tensioner, its a dampner.If you check the chain with a socket on the crank and remove the dizzy cap and watch the rotor...the slack in the chain will hit the dampner and you will assume its still tight.So checking it like this is not an accurate way.I removed it(dampner) and could clearly see the amount of slack in the chain.In other words,if you have close to hundred thousand miles on your v6 ..get the chain out of there.Its not a heavy duty item..My flat spot and RPM dipping is gone,the car runs like new.I was so amazed..I found a chain and dampner at auto zone for 35 bucks(Cloyes),they do make a roller type for about 100 bucks.If you end up doing it..change all the water pump bolts from Torx bolts to regular ones.If anyone wants more info on this..send me an email.

 

i always assumed the timing chain could be a possible problem but i thought it would be a pretty major thing to replace.. how difficult was it?

and also on my backfire issue i found out that my egr tube that goes to the intake had 3 holes in it so it was causing something like a major vaccum leak.

i replaced the egr and tube with one from a junkyard and the backfireing is not that bad anymore but i think the chain will make the car run like i want it to.

 

The replacement wasnt that hard..you will need a puller for the crank gear and the harmonic balancer.Remove all the water pump bolts,and had to remove the P/S too.Just unbolt it and swing it over..theres one bolt that needs access and its in the way.Remove all the water pump bolts..they are torx heads and I had some crappy sockets that just rounded off.So after getting a better set Torx sockets, I removed all the bolts ,one was a pain it was seized.So after beating on it ,I replaced all the Torx water pump bolts to regular bolts.Theres 3 smaller torx bolts(reused those) that hold on the timing cover and I also removed two small nuts that hold a wiring harness underneath the balancer..I dont think you need to remove those but I did anyway.Thats it ply off the cover and you will see the dampner held on by two bolts remove those and then see how much slack is in the chain.My gears were still okay it was the chain that was worn.I had problems starting the engine sometimes and I dont think this engine spins a full revolution anymore before it starts.I can feel the tightness in the motor too,trust me if you never been behind the cover,and just want to check it... the cover gasket is like 8 bucks and comes with a water pump gasket too.You cant go wrong.

 

I wanted to add a few more things..they do make a roller type chain for this motor ,but I was told the dampner will need to be modified.I'm assuming you might need to take some rubber off the sides of it to fit it correctly.Not sure..maybe someone already has done this.I have had this car for almost a year and I have changed everything in the ignition,everything in the fuel..and by the way a BBK adjustable fuel regulator for a TPI will fit our V6 just need to get a smaller adjusting screw for it.I even replaced all the computer sensors including upgraded to a 92 ECM.The replacement chain was the best thing I did ..this car runs awesome now.Its almost like I dropped in a fresh motor..seriously..Its a whole different car.

 

Just talked to Auto Zone and they have the OEM replacement chain and gears for $27.00 and the roller type upgrade for $36.00. I figure I put 130,000 on the original, I think the OEM will do just fine. May do the job this weekend, maybe Thanksgiving weekend.

Thanks for the tip !

 

jstrdn90rs, had the timing chain skipped a gear before you changed it? Or was it still spot on and just loose? I am having these same symptoms but it is so bad the car is undriveable.

 

Mine was virtually undriveable I did the timing chain kit. My chain was really loose it had about and inch of play in it and the damper had a big chunk broken out of it.

 

Mine was still on ,but was really loose...The one thing I noticed that cleared up was the double dropping of the rpms when I came to a stop.It would drop almost to nothing and recover and then drop again,just before the car came to a stop.Once I did the chain,its smooth no dropping of the rpms.