PLEASE HELP high rpm power loss

hey guys ill start by saying im asking for help because i just lost to a golf. ive got a 03 gt, so its 3.8 n/a, ive got 180000 km(or 110000 miles) and im having MAD trouble. at high rpm (around 4700) my engine stops making full power and if i hold the gas, it gives me a check engine light. the code is for cylinder one misfire. so i changed the plugs and wires, as well as the fuel pump and ran 3 bottles of injector cleaner. nothin. then i switched my coil packs and ignition control module and still nothing. i have a slp cold air, so intake is good and i use mobil 1 and 94octane. also this is my second transmission. please help my car needs you.

Welcome to AF.

Lost to a Golf? :lol: But seriously the GTI version of the Golf is no slouch.

It looks like you have most bases covered. Have you checked out #1 fuel injector? Noid light test it, check injector coil resistance or swap it out with a known good one from a cylinder that is working.

Also, just to rule it out check the MAF sensor.

i unpluged the maf and nothing changed. im pullin the rail and injectors tomorrow just gonna swap one and three and see if it jumps cylinders, if not ill check the cat.thanx ill keep you guys posted.

Have you changed the fuel also, and the fuel filter.

yes ive tried other fuels. also i had to order new o rings for the injectors so im getting the cat tested tomorrow and ill pull the injectors when i get my parts. thanks for the input ill keep u posted.
AF is some dope azz shiznit

AF is some dope azz shiznit

I'm glad you feel that way!

If your getting a P0301 (cylinder 1 misfire) Then I dont think the cat is the culprit. A partially plugged cat will cause a P0300 (random cylinder misfire).

Have you tried swapping the injectors like what was suggested?

How about a compression test?

ya so my cats good so i switched cylinder 1 injector with cylinder 3. now when it hits around 4700 it ceases to climb any further and acceleration it halted (ie its missing). but it does not however give me a trouble code or check engine light. im wondering what you guys think, did i find the culprit.

I would suspect the injector. Drive it like that for a few days and see if you come up with a P0303 Missfire code instead of a P0301. This would confirm the injector is flaking out on ya.

Lack of power hints strongly at a fuel issue....I would agree that if the injector is bad you should get a cyl #3 misfire code.

If not...I'd look at your fuel pressure at the rail...the pump could be on its last legs.

so guys injector was bad swapped it with a good 1. BUT. now im getting random misfire and a MAP code. phuck me sideways. i finally bit the bullet and went to gm. 100$ diagnostic test later they say i probably need new upper and lower intake gaskets. probably. i was like dude 100$ and probably. yes probably. soooo any input on this would be great. also i got a gtp i totaled (well was driving when a bitch in a mustang gave me the P.I.T. manuver at 60mph in the snow, third week i owned it, im not bitter) i bougth it back from insurance for a g and engine and tranny are still together and in good condition just no trunk or rear suspension (looks like a crx). do i need to swap the complete wiring harness to put my gtp engine in my gt or can i just splice a couple connectors on. thanks guys

UIM and LIM gaskets huh? Did they tell you what your fuel trim readings were by chance?

ZZP sells a wire harness that allows you to swap in an l67. However keep in mind that along with the motor and wire harness, you'll have to get the trans, axels, and fuel pump.

Couple of things...you could actually have a bad control sensor...what is the actual code?

Also...if the lower intake gaskets are badly shot I'd think you would be consuming coolant at minimum or overheating if worse...

i think the code was po107 what sensor are u talkin about? also i got all the tranny and axels but does anyone know if i need the sub frame from the gtp they look different. and will i need to take off the tranny and lift it out or just undo the subframe drop it and bolt up th s/ced engine and sub frame. cause for 100 bucks for the harness, fuel pump and fuel pump wiring ill be droppin the gtp engine as soon as i find out about all the necesities.

Probably a moot issue now but bad LIM gaskets especially a bad front bank port gasket can set off a MAP DTC so it is not uncommon. The diagnosis on the intake gaskets being bad is probably correct. The best way to tell is pull the MAP sensor and do the taste test. Also, remove the PCV valve and check for coolant where it mounts to the UIM. If it tastes sweet then it is coolant. In addition there should be notable coolant loss.

ya thats the thing no notible coolant loss. its a little lower than when i changed it in december but nothing really. ill start a new post for the swap. i still want to get this so i have a good engine and tranny to sell considering the trannys only got like 25k on it in kilomoters.haha ill look at the pcv valve tomorrow. thanks for the help

thanks guys fixed it, did the uppers and lowers (maybe the old dexacool?)and got a cat for a good price from a buddy that bought two for his(dual exaust haha). anyway its runnin better than i remember so im happy. thanks

Anytime you take this motor to the dealer with this many miles they are going to say "It could be the intake gaskets" because the intake gaskets always go out on theese. Do yourself a big favor and install good quality aftermarket gaskets while the motor is out.