Misfire Cyl 1 & SES Light [Archive] - GrandAmGT.com Forum


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04-30-2008, 06:37 PM
Hello Everyone,

Im new to this fourm. Ive read alot of posts and done alot of searches on the problem im having and think I narrowed it down to either a lower intake gasket leak or a head gasket leak seems like these cars are known for it. I just figured Ill post because I couldnt find exactly the same symptoms and get your guys input. First when I got the car 2 weeks ago a, 99 gt 3.4L I had a problem with it running hot and blowing coolant out the overflow tank hose when the car got to about 210deg. The problem was someone had put a overflow cap for the 96-98 model year on mine 99 and it would never hold pressure and boil out (diffrent style tanks). So I got the correct cap and everything was good till yesterday in which the car started to run rough at idle when in gear and I got a flashing ses (bad misfire) then it turned steady. I started to smell either a rich condition or the clogged cat burning smell. I also noticed that every so offen, not when I rev it or drive and not all the time, but if im sitting idle I get a little white smoke/steam out of the tailpipes every couple of min then it stops and starts. I noticed a small amout of water in the lip of the exhaust tip. I checked the coolant level and it looked low considering I flushed it when I found the cap problem and it was full then. I plugged my scanner in and it told me that I had a misfire on cyl 1 so I reached down and moved the wire around on the cyl, fired it back up and it seemed to run a little better but not much. I then put new plugs & wires ac delcos and bosch wires. When I fired it back up again no codes It did still have a constant miss but it seams much less there. The car didnt loose any power. I drove it around the block pulled into the driveway and let it idle for a few min it which I saw a little white smoke/steam for a second and the ses light started flashing again when I was looking at the tailpipe I could smell the rich/burnt cat smell. What I see left is to check the coil pack but usually if 1 side goes they both go plus the rich condition, Check the injector (I did do a good spray of TB cleaner when I got the car), if neither of those the only thing I can do is a compression check and if that fails its the head gasket or of not and compressions good (i think it supposed to be around 165-175psi) can the lower intake gasket leak coolant slightly into the intake runner which would go into the cc and cause the misfire and white smoke/steam but it seems like a constant misfire which would lead me to compression. Anyway let me know what you think and imput is appreciated thanks again Eric

05-01-2008, 06:01 PM
Just an update I did a compression check today after work and all cylinders read between 130 and 135psi except for the one that was misfiring which read 122psi. I also noticed a loss of coolant the plug was wet in the misfiring cylinder, and more noticeable it was blowing out more of the white smoke/steam. I did just for checks, run a fuel injector cleaner that you hook up to the fuel rail and disable the fuel pump. It seamed to run better for a few minutes but then went back the the sputtering. It did run smooth for about 10 min untill it heated up, and 12 psi diffrence between cylinders is not real bad. Could this just be and intake gasket since it did run good & no engine light for a little when I started it. It only seams to happen when it heats up. Any Ideas?

05-01-2008, 06:09 PM
I'm no profesional, but I'd say Its either a lim or head gasket.

05-01-2008, 10:19 PM
Head gasket would be my guess.

05-02-2008, 02:03 PM
Yup its starting to get worse, rough idle, run hot and loose coolant fast so I just ordered a whole gasket kit for the, upper, lower, head, throttle body, exhaust plus new head bolts. Ill start tearing into it tonight when I get home and report what I find out.

05-03-2008, 01:26 PM
Well just got everything apart all the way down to the head gasket and sure enough there lied the problem the gasket was eaten away around the water jacket by the #1 Cylinder. Plus the piston was nice and clean. So I cleaned eveything on the block which looks good no gunk buildup. and the entire top end is getting sent to get checked, machined flat and cleaned. so hopefull Ill be able to get it back together by monday night.

05-05-2008, 12:15 PM
I had a misfire on #1.

Was the head gasket.
and I was losing compression on two cyls.

[kind of like you are on the one]

I did the same exact thing, tore it down to the gasket, machined the heads...
Now it runs perfect

05-09-2008, 10:18 AM
yup finally finished putting it back together last night. I had the heads and intake steam cleaned also plus I cleaned the injectors and replaced the fuel filter, oil filter with synthetic oil, pcv valve, delco plugs and bosch wires. It runs like a top so far, you could ballance a dime on the intake it dosent even so much as hickup. So knock on wood that should take care of those gaskets for a while.