2.4l max running like crap ECU????!!!

I will try to describe this the best that I can... I just bought the truck knowing it was running a little rough assuming it needed a tune up. Well as I looked closer I realized everything looked pretty damn new plugs, wires, cap, rotor, air filter, even the fuel filter looks new. The truck sputters a bit and then clears up in the higher rpms sort of like it is misfiring. The previous owner had the timing belt changed and thinks maybe the belt wasn't changed properly. How possible is it for the belt to be one tooth off? Is there any way to check to see if it is in fact off a tooth if so how? Before I tackled that project I would like to check the timing any tips/ how tos on doing that? What else could it be? I really do not want to mess with timing belts as I have never changed one before so I would like to try out all other possible scenarios before I go the timing belt route! I paid 450 for the truck it has 130k 1 owner I would like to keep it for awhile..... Here is a picture

To check the alignment of the timing belt you have to first bring #1 piston to top dead center. Pull the spark plug and insert a straw, or something like that, into the combustion chamber, resting the straw on top of the piston. Turn the crank until the piston is at absolute top of the stroke, the timing mark on the crank wheel lines up w/the timing marker, and the rotor is pointing at #1terminal of the dist. cap. If any of the marks are off then the belt is probably improperly installed. The exception would be if the rotor is pointing 180 degrees out. In this case spin the crank wheel one more time, w/the piston back up, and look at the marks again.
I'd also take a compression test, with and w/out a squirt of oil, to get a baseline compression reading, and hook up a vacuum gauge to check for leaking vacuum.

Hi Samario1984,

Since you said that the misfire goes away at higher rpms, I doubt your timing belt is off one tooth. If the belt was off, your misfire would not go away. Your compression would probably be low, since the valves are not opening and closing at the proper time.

You can check the timing belt is in the correct position by removing the upper timing belt cover (three bolts). Turn the crankshaft clockwise until the alignment mark on the camshaft is at the nine o'clock position. The timing mark on the crankshaft pulley should be at zero degrees. If both marks are correct, the timing belt is installed correctly on the crank and camshaft pulleys. Refer to your shop manual to confirm these alignment marks.

Never not turn the crankshaft counterclockwise, only turn it clockwise. if you turn it counterclockwise, you will release the tension from the timing belt tensioner.

I believe you can also use this procedure to find TDC for cylinder number one.

Perform a compression test to check the condition of your engine. While you have the plugs out, make sure they have the correct gap.

John

Ok, I would rather not start a new thread but I have some more questions.... I checked the timing belt and I am almost 100% sure the timing belt is on correct and the timing is 5 degrees before top dead center. It is possible that the t belt is off one tooth but I really do not think so... I did a compression test and it read 180 which is obviously extremely high.... I googled high compression and one of the causes was carbon build up. I did the whole sea foam clean the carbon trick and it smoked like no other.... Truck still runs like dog crap.... I did just order a new coil for the truck... Per the manual the coil should be between .72 ohms and .88 ohms mine measured 1.1.... I doubt that is going to fix it but i hope so. Is it possible my ecu is bad? How can I check it? they are wicked expensive and I would hate to order one and be stuck with it... I did just clean my egr valve it was caked with carbon and checked pcv valve. Still running like crap! Any ideas or suggestions would be greatly appreciated... i would much rather be buying drop spindles, springs, and lowering blocks for her then this crap!
Thanks In Advance

Your problem my be your throttle positioning sensor. I test drove a truck I was thinking about buying that started and idled fine but ran like crap until you got up to speed. I decided not to buy the truck at that time. I checked on it a week or so later to find out that the car lot had sent it to a mechanic and found the tps had went bad. Hope this helps you.

Check the air gap on the distributer pickup. If that is good and injectors are good it is likely the ECU. Look on Ebay...good ones come up sometimes at decent prices <$100.

Thanks for all the help guys... It ended up being number 4 injector was rendered useless due to being clogged entirely! replaced injector 4 and she runs like a champ... Now on to lowering!

How did you go about checking your injectors? I'm having a similar problem with my 2.4 and I'd like to check the injectors out before I go replacing expensive sensors.

I removed my injectors and took them to a local franchise called Doctor Injector, where they tested the spray pattern and capacity. $ were about 80% clogged, 2 were about 30% clogged. Had them cleaned and reinstalled and the truck runs fantastic. It cost about $32/ injector but was well worth it. I am curious if I could have cleaned them with an Utrasonic cleaner myself?