Got a cheap 04 GTP, has a couple problems..

**down2earth** · 02-07-2020

hello guys, Im new here to the forum.

I bought an 04 gtp for real cheap, has a few problems.

during start up it smokes real bad out the exhaust and runs rough, did some homework and had my coworker do a full live scan.

CEL codes it showed p0300- multiple missfire, p0128 thermostat

digging more into it we found that cyl 1 and 2 had the same excact amount of misfires at pretty much the same time. no other cyl had any missfire. i pulled a couple spark plugs from the front of the engine and they seemed wet and black.

did my homework and figured it was the intake gasket? because cyl 1 & 2 run off different coils. so i went to the store and got a complete intake lower and upper gasket. got some plugs and new wires. hoping this is the issue.

hopefully someone has some more insight and has a few pointers, also on the top of the s/c theres a vacccum port that has 3 nipples on it and the previous owner plugged one of them with electrical tape. Ill get some pics up and also took a video of the scan which shows just about everything.

im hoping to get it running right over the weekend.

**Scottydoggs** · 02-07-2020

the 300 code could just because it needs a tune up bad. one is the plug closest to the coil packs, 2 is the one by the alt.

that vac manifold the one jipple with tape should be capped off in a 04 car. you can buy vac line caps.

does it smoke all the time? or just the one time? or at every cold start? valve seals come to mind if its oil you smell out the pipes.

04 iirc might have the new metal intake gaskets factory, so chances are lim gaskets are ok. the blower might have metal gasket, if it does you can reuse it. its 40 bucks new...

**down2earth** · 02-08-2020

It smokes constantly, my neighbors probably thought I was sending smoke signals. It doesn't seem blue, but stinks like heck. I got the car about 100 miles away. I towed it back because it was running so crappy. I opened the hood after that and seen red fluid sprayed all over. Figured it was coolant.

Then when I got it back it hardly had any oil on the dipstick so I put about 3 qrts in it. The radiator had coolant in it but the resivore was dry.

So you think I should do the plugs and wires and give it another shot?

Oh, and the plugs seemed black and wet. Let me see if I can get pics.

**down2earth** · 02-08-2020

Oh also it has 230k on it. No previous paperwork. The guy I got it from didn't know very much about anything

**bandook** · 02-08-2020

I'd pull the valve covers and check if any valve seals have popped. Your situation sounds a lot like what I dealt with. Constant misfires and smoke. I had blown out lower intake gasket and a popped valve stem seal.

**down2earth** · 02-08-2020

I'm out changing the plugs and wires right now.

Should I not start it up incase I foul out the plugs? Or should I give it a try and see if it fixes the miss?

Also can I pop off the front valve cover without having to remove that bracket that goes to the passenger side of the engine? Also what would I be looking for for the bad valve seals. Can I upload pics from my phone to show you guys?

The number 2 plug I pulled was wet and black and smelled like gas/ oil

**Scottydoggs** · 02-08-2020

red fluid would be tranny fluid, so its got a busted line, if its spraying around the rad the line might be disconnected from the rad.

if its smoking full time, thats more then valve seals, thats a dead engine.

black smoke is raw fuel.

blue smoke is oil.

white smoke is coolant. and thats a head gasket most of the time in a supercharged car. rare, unless the cars been over heated real bad.

**Scottydoggs** · 02-08-2020

oh. take all the plugs out. then crank the engine. have some one looking for coolant to shoot out a plug hole, or see if the one or more of the plugs is wet with coolant. if its a head gasket the coolant leaking into the cylinder can cause the misfire.

bet a bottle of blue devil would fix ya up pretty fast too. search for vids on yt, they start out blowing white smoke and 30 minutes later its all normal running.

**down2earth** · 02-08-2020

Dang I was hoping it wasn't a head gasket. I got all the front 3 plugs replaced. I didn't see your post in time. Well I got it for 300. I think I'll change the plugs give it a shot and put it back on Craigslist. We need a running car now. My gf rolled our trailblazer and we're low on cash.

I should be able to get 500 or more right?

**Scottydoggs** · 02-08-2020

if its bellowing white smoke drop a jug of blue devil in it. its like 30-40 bucks.

**down2earth** · 02-08-2020

Ok I'll do that for sure. Got 4 plugs done so far. Am I able to drive it to the store like it is to get the blue devil?

**down2earth** · 02-08-2020

Do I just add it to the coolant? Or how does it work. Never used the stuff before.

**down2earth** · 02-08-2020

There's stuff called bars that you just add to the coolant. The blue devil says you need to flush the system and remove the t stat.

**Scottydoggs** · 02-08-2020

do not use barrs stop leak, thats do nothing trash that gums up the system bad. its like tar pellets.

blue devil is clear liquid.

directions are on the bottle. remove the t stat, flush the old coolant out to clean water, then add the blue devil and run it till it stops smoking, then you drain the system of about one gallon. then add one gallon of full strength coolant, not the pre mixed jug. one gallon to the 2 gallons left in the engine is a -20 mix.

**Scottydoggs** · 02-08-2020

heres my coolant flush procedure iv posted here 100 times lol

remove the t stat, put the t stat housing back on, take the upper hose off the radiator, then push it down to the ground to a bucket or let it fly.

get your garden hose out, put it in the rad turn it on, then fire up the car, let it run till clear water pumps out the top hose.

then turn the hose off, run the car till no more water comes out the upper hose. then turn it off.

put your t stat back in, with new gasket, the upper hose back on.

now take 1 gallon of full strength green antifreeze, not the 50/50 crap. ( parts store cheap green is fine to use) dump the whole gallon in the radiator, fire up the car, fill the rad with hose water till its full. top as needed till its ready to be bled of air. it will burp and take coolant as the water in the block warms up the t stat opens up for a few seconds till cold coolant hits it and it shuts again.

now to bleed the air out, let it idle rad cap off till the fans turn on, (when the fans are on the temp is over 195 deg, the t stat is wide open) then open the bleeder screw on top the t stat housing a few turns till a steady stream of coolant comes out the hole, shut the screw, top off the rad. cap it"

**down2earth** · 02-08-2020

Ok I watched the video. Answered some questions lol.

My issue is now is it going to mess up my new plugs? I just spent half hour on the PITA plug.

**Scottydoggs** · 02-08-2020

if you have some clear thin tubing, you can put the tube down inside the rad then siphon it out to a gallon jug, then just put the new coolant in the rad and run it for while, then put the t stat back once its cooled off. then if you need to top it off, use the blue devil wwater you sucked out to top off.

i used this stuff my self. my old 3800 would eat 2 cups of coolant. bd stopped the eating of coolant. but if you flush the coolant you will need to install more blue devil. mine started to eat coolant 5 years later when i did coolant change. had to add more BD.

**Scottydoggs** · 02-08-2020

Originally Posted by down2earth

Ok I watched the video. Answered some questions lol.

My issue is now is it going to mess up my new plugs? I just spent half hour on the PITA plug.

plugs are fine

**down2earth** · 02-08-2020

Also when I was doing the rear plugs I noticed 2 sensors right next to each other. The one on the right ran to a plastic hose and the one on the left had an open nipple. Does that go anywhere or should I plug it?