MSP Help! Rough idle and loss of power

[black n yellow]

I have an 03 protege speed. So I changed the ignition coils because from what everyone was saying about them it sounded like it could be that but it wasn't and i was going to change the fuel filter. My car is not accelerating like its supposed to and acts like it wont go until a much higher rpm, its like theirs no power. it works fine when the car is cold and pulls hard like it is supposed to but when the car is completely warmed up there starts to be a rough idle and wont go, at stop the idle bounces and my exhaust sounds like its an old tractor with a putt putt putt kind of noise its not normal it sounds like its going to give out. I had a timing belt replaced previous. All my hoses are hooked up right with no cracks or holes. The only thing i have done to it is a CAI and a full downpipe catless exhaust. Not sure what it could be at this point if it is the fuel filter or boost leak? I'm stumped on what to do. please help.

 

[Nc MSP]

sounds like your hitting fuel cut.... mine was doing the same thing so i also changed the coil packs, it helped but didnt fix it. so now im thinking and have been told its the wastegate actuator. i just ordered my new one, once i get it on i can let you know if that was the problem

 

[Nc MSP]

if you have a boost gauge check and see if your spiking above stock boost.

 

[f1yen]

Do you/ a friend have a automotive scanner? check for your Long term Fuel trim (LTFT) this will tell you if you have some leaks. Long term fuel trim is the difference accounted by the computer when cruising/idling comparing the MAF input to the O2 sensors. LTFT is the "learned" behavior of the car.

So this is effected by both intake and exhaust, SO MAKE SURE AT LEAST ONE OF THEM IS SEALED GOOD, preferably the exhaust header to block.

If the LTFT says -20% means that in order for the ECU to command stoich AFR (which is where it is programed to run), it is giving the engine -20% of the fuel that the MAF says the engine should need. In this way there is extra air leaking out somwhere between the MAF and cylinder (remember to check intake manifolds!)

Or your intake is boost leak tested (at least at the pressure seen by the car), and no leaks!, but your LTFT says +15%; so your ECU is assigning +15% more fuel than the MAF says you should need. You may have an exhaust leak and you are running overly rich, just so that your sensor will read stoich.

Just keep in mind this is based off of the O2 sensors and MAF, so if you have intake leaks and also have an exhaust leak, then you may be chasing your tail!

Hope this helps! (correct me if im wrong, trying to do this by memory)

 

[black n yellow]

Let me know if its the wastegate. Thanks and I don't have a boost gage. I know I have a bolt missing where the exhaust manifold bolts to the block because it broke off but the intake is real tight on there ill go through and make sure everything is on properly and check for the codes. As for the fuel cut it wouldn't have to do with the fuel filter? Just the 02 and maf reading wrong?

 

[black n yellow]

No check engine lights either

 

[Mustard97]

i'm pretty sure our cars don't have a changable fuel filter.... take brake clean and spray down the intake to head area and some of the intercooler stuff too and see if it makes the car bog down or run better, just DON'T spray the hot stuff.... also get a vacuum/boost gauge and find out what vacuum your car is at when idling.

 

[pbarton14]

Same prob going on in my msp, I was told its the ecu, I idle at -20 spans it boosts just fine. No leaks

 

[black n yellow]

Its in the tank with the pump for the filter. It would explain a lot if its the ecu. Ill have to get a gauge and see what its at. Thanks guys if anyone has any other suggestion please help.

 

[black n yellow]

Whats a good system to buy to replace our ecu?

 

[Mustard97]

the "filter" thats attached to the fuel pump is just a screen to keep the big stuff from going in... i don't consider that a filter.

 

[ND4MSP]

Subbed, long shot but try cleaning your iac valve. One of the easier things to get to. My wife's mpv would shut off randomly and this cured it. Don't know if this would solve the major loss of power until the car gets the higher rpms. I have all of the above. I had a cel for one of the sets of flappers in the intake manifold at one point when the car went through the super loss of power down low. I seafoamedmy speed for s**** and it went away. Not sure if its a couinsedence or it really losened up some crud in there.

 

[black n yellow]

Ill have to give that a try and see if it works. Maybe I'm drawing a blank but what's the iac valve?

 

[Mustard97]

idle air control

 

[Jo060]

I don't think anyone mentioned cleaning the MAF sensor...Have you tried that? It would be a simple fix.

 

[black n yellow]

No haven't tried that. Today my check engine light came on and got a p0300 random misfiring it said but it was the only problem so not sure what it means or could be due to?

 

[black n yellow]

Ill try that too I already have the stuff. My check engine finally came on and said p0300 random misfireing I guess not sure what its due to?

 

[Mustard97]

that code is set most likely due to your car misfiring, p0300 will usually set if there is more then one cylinder misfiring, have you checked your plugs? what color are they? check the ceramic part for carbon tracking (black lines that you can't wipe off) some times a misfire in one cylinder will cause that light to set due to ecm not being able to determine which cylinder is misfiring

 

[ND4MSP]

Iac is located on top of the throttle body. Held on by torx screws. I haven't done it on my speed yet. Also a short story, my car started misfiring really bad and had a cel also. I checked it into the shop before I knew any better. They dicked around with it swapping coils and such and said it was running better the next morning. Hardly, but anyways I brought it home and took the airbox off to clean the maf and the diffuser cone thingy was loose sitting sideways causing the metered air to pass around the sensor. Fixed and misfire was gone.

 

[Jo060]

Like ND4msp said, check your plugs/gap. It's crazy how much an incorrect plug gap will change how your car runs.