Hey guys, my 2.8L v6 (MPFI) is crapping on me.

She ran GREAT until i changed the lower intake, then when i replaced that, she runs like crap... so i'm sure its something that i did. I replaced the gaskets on all intakes, and the lower intake to head gaskets... and the valve cover gaskets. the car is acting like it is bogging down. she will get up to about 80 on her own speed, flooring it on the highway (used to be easy to get to 120) and this takes forever. i untightened the rocker arms so i could put the gaskets on there... i think it is a vacuum problem, but i sprayed carb cleaner on the whole engine while running, and a ton of water.... nothing happened. it didn't rev down or rev up when i did that. when i put it in drive and go for it, it sounds like a slow and furious lawnmower type of thing. she shifts hard, which is not normal for before. also the brakes really suck right now, they were good before. so, you will say a vacuum leak? well let me know what to do to test more. i have already replaced all of the vacuum lines a couple of months ago. i have checked 4 times and made sure that everything was connected. does anyone have any other ideas??

thanks!

Scott

long story short: i replaced the lower intake and now my car is acting funny.

 

more stuff to add: it is idleing high... 2250'ish versus the old 600-1000 (can't remember). now, in gear it will "idle" down in the 1200's. i think i have the rocker arms set wrong, i'm also hearing a rattleing sound, and it is drinking a lot of gas. the brakes are doing better, like they used to be, and she will get up to about 85 on the highway, but it feels like she has no torque at all... no thump to the gas pedal. now, she is still slow because something is wrong... she is also sounding like i have something mis-tuned... the exhaust sound is weird... the lope to be specific.

 

how did you adjust the valves the way i was taught was to tightten them down till three threads show the start car with covers off and adjust one at a time by looseing till it get noisey then tighten till noise quits and give it a half turn more this method seems to work good for me
goodluck
luke

 

The problem with this is the manifold has to be off to get the valve covers off .
Scottyb,
With the idle being that high, I'll have to say you've got a vac leak (possibly in the booster vacuum line). Are you getting the "check engine" light blinking or staying on?
Why did you replace the manifold and/or vac lines if you said the car was running great before?

 

The brake problem would be the brake booster having a leak.

 

the brakes work normal now. it was a cracked line... i have replaced all of my hoses before, except for the small plastic ones that run throughout the system near the manifold. well, one of them had a few cracks at the bends in the small tubes. i touched one and it fell apart lol. i replaced that and they work good now. I will adjust the valves with the covers off... but i have to go and put everything back on, and thanks for that info! I'll get started on it right away. I did it as the chilton and haynes manuals told me... but they didn't account for human error. when you tighten it, the hydraulic pressure makes them go back down again and "loosen" up.

Thanks guys! I'll let ya know whats going on tomorrow after i try and fix it.

 

Don't forget that oil is going to squirt out of the pushrods with the covers off. I used spray adhesive to glue the gasket to the manifold. Then put a light coat of oil on the other side of the gasket. So when I pull my manifold off (sometimes will be often, lol) the gasket can be re-used several times. This also worked good on the valve covers.

 

yeah, i used some cheap o'reillys oil that was laying around to coat the the bottom side of each gasket, so the gasket would stick to the top that i was taking off... such as the bottom of the plenum, and the bottom of the upper intake

as far as it goes now, i have the valve covers off and everything back in place, and will start her in a few minutes. i'll post back in a few hours when i'm done

ScottieB