this 156k engine has been using a little antifreeze..the check light came on about a week before the shuttering at idle and run. With the cold weather i just went ahead and replaced the map and mass flow sensors in hopes it would take care of the problem.. no change.,I saw some anifreeze in one of the pocket in the lower intake manifold the side that is closed to the firewall. With all the intake problems these have I changed the plasic intake ( disappointed as i did not see any problems around the egr input)..I removed the lower intake and the seals looked broken/bad ( plastic seals )..with high hopes replaced this with a felpro steal/rubber gasket..torqued down as required and reassembled..same problem..Also someone had mentioned the connector on the mass flow which I pined the wire and checked connections on the connector ..ok.. It acts like a blown headgasket to me but not sure..If its a blown gasket would I see bubbles in the radiator as the old cars? If so do I have to wait till its warmed up for the thermostat to open ? Before pulling plugs when is the best time to do it after engines runs for a period of time? Maybe I''m going the wrong way. I appreciate any help ideas, other posts that relate...
Thanks

 

what year?
miles?
age and manufacture of plugs?
age and manufacture of plug wires?
are plug wires numbered?
are you sure the pcv oring, pcv spring, map housing oring and map seal are installed correctly?

 

1999.lesabre, 156,000 miles..Today replaced all wire yes some still had factory numbers..Installed Bosch wires and AC delco plugs .060 gap..Numbered old plugs as I took them out..other than were up to .090 gap none were real clean as if antifreeze was getting into the cylinder. (per someone local idea). remove the pvc out of the old plastic upper manifold and compared installion of the new one I put in ,so the new one is the same. recheck fitting on plug wires after install..
Still similar if not same problem but now I'm getting P0300 misfire...Rechecked plug wires again . I check the connector inline to the coil packs,,in process of checking coil pack coils and will recheck fuel pressure.
Greatly appreciate the response..
Other notes
I should have check the codes after I did the intake gaskets..
I have relaced the fuel regulator and crankshaft sensor a few years ago.

 

All three coil packs check the same about 0.9 ohms on the primary..Fuel pressure about 42psi idle and holds when accelerating..pressure goes to about 60psi when I pull the vacuum to the regulator.. no signs of gas at that port of the fuel regulator.
Still getting p0300
any ideas greatly appreciated.

 

is the p0108 code now gone?
do you have the ability to check misfire history(p300)?
i am skeptical of anything made by bosch. i have seen brand new "budget" plug wires cause misfires.

 

Yes the p0108 is gone. No I dont have a way to tell the history of p0300..Before I started the work I had reset the errors codes 3 times. on the 1st time I had 2 -P0108 and a code for thr oxygen sensor. the second two times was only p0108..
I didn't know bosch was budget wires..
I have gone over my work several times trying too figure out what I may of done wrong,. as for the fuel pressure when I pull the vacuum line to the regulator and put my finger over the vacuum line the fuel pressure goes to 50psi but no change in the miss.I pulled other vacuum lines and plug with my finger to test no difference..I left the fuel pressure guage on the car (ignition off) for about 4 hrs this afternoon while I was away the pressure stayed at 45psi.
Again I checked that PVC valve installation just like the old one.

 

Just in case I just put both the old Map and mass sensores back on. no difference..They both have seals which if for instance the mass flow has a O ring which if missing may of caused p0300.
In appreciate your ideas..You are probably thinking on the same lines as mine didn't have the code before so must have been something I did or something I moved which failed, connectors ,wires,..But my understanding this p0300 is multible misfire common causes vacuum leaks ,spark,exhaust blockage.

 

misfire history would be VERY helpful. how much did you spend on the plug wires?

 

I didn't think my answer thru about the miss fire code history before..I didn't have a p0300 before i started the replacements of tha gaskets. So the p0300 started after i did the work. how much time i spent on the plugs? the ones close to the fire wall were a bundle of joy . #4 wire broke as i was tryning to twist and pull those off. all of them were difficult 2,4,6 more do to the little srea to work in.

 

sorry, how much $ did you spend on the plug wires?