Dexter

hey my car just started doing this:

I'd turn it on, and then the idle seems a bit rough (it dips then it catches itself) then I'll get it going. Sometimes the shakes stop, but other times it keeps going. I was on the highway the other night and I could hear the engine "knocking". Please help! I have a roadtrip with the MAX down to Florida soon and I don't think I should drive her that far in that condition. Not getting any codes off of it except Rear O2 sensor overheating but that has been there forever and since I don't live in an emissions state I don't worry about it.

Recent adjustments:

-Replaced cyclinder 3 fuel injector (w/ OEM)
-Replaced IACV (w/ Autozone part)

I did check the motor mounts and found the upper passenger side one a little loose so I tightened it up.

Paintguy84

Sounds like another one of your fuel injectors to me. If one goes, sometimes others will too. I would check those first.

mas324

Check the fuel injectors, air filter, and maybe do a seafoam. If it continues, get a new motor.

Paintguy84

If it continues get a new motor? Way to really troubleshoot a problem LOL. Seriously I would check those injectors buddy.

tfunkadelic

Injectors.

Dexter

FML! the last thing I need is to have to replace ANOTHER injector. will check other injectors though and sea foam it. air filter is good.

cashoit

u might need new mounts. If its engine knock then replace KS

cockymax

Mine does this also..but very very intermittent..it really feels like a skip but i don't know..I just changed the fuel filter and air filter...but it still does it.. .I do know I need a water pump and am doing that this weekend...

95franklin

Read, in the how-to section, how to check your fuel injectors and ignition coils. It will save you time and money. If it's not either, then you know you have a different problem. Also, check the resistance of the knock sensor (also in the how-to section) to make sure that you actually need one. Good luck.

mejiseike

my max just started doing this too, it doesnt dip or anything but at idel the car will shake, not bad but noticeable, worse then the normal no shake/ quietness of the car

VTonmymind

iTrader: (1)

If it continues, get a new car.....

mejiseike

want to... so bad....

VTonmymind

iTrader: (1)

Aw dude. Once that bish starts running right it'll be aight. Check them plugs or coil packs yet?

Dexter

Will check resistance of fuel injectors. Checked motor mounts they seem fine.

Shouldn't I expect to get a misfire code if it really is an injector going bad (like I did when the cyl 3 injector went out)?

Spyguy

iTrader: (1)

Check your MAF too.

Dexter

how do I check/test the MAF?

Dexter

cyl #1 - 23 ohms
cyl #2-6 - 16 ohms

the one I replaced before was cyl #3 I guess it's #1's turn to crap out on me. FML! I still don't understand how I don't have a code yet.

grancouva2000

i had the same problem and i used tectron fuel cleaner and stop for now.

Dexter

I got some fuel injector cleaner in it but I will try again, if all else fails I will just have to deal with replacing another injector, this time I will go ahead and replace #5 too so I don't have to deal with that BS for a while.

stokerdevil666

iTrader: (3)

when i had this problem i had a dying coil pack i was throwing a blinking cel as a result of the multiple random misfires. i poppeed and replaced all the coil packs, well replaced inn te sense of making sure they were nice and snugg snugg, and the problem cleared up for me. if you wanna check your coil packs, WITH THE CAR OFF shove a screwdriver preferably a flat head into the coil pack, into the part that attaches to the spark plug, and touch it to some metal nbow turn the key it will spark, a very strong spark DO NOT TOUCH IT, you are good leave running for a few seconds 500-600 RPM wich is what your car shuld idle at if manual between 700 and 800 if automatic, this will cause a "fire" signal to be sent multiple times look for an iregularity or a pause in the sparks if none after about 5 seconds. turn off car remove screwdriver and move to the next one. if there is hesitation or gaps you found your culprit hope this helps

jholley

iTrader: (13)

A lean air/ fuel ratio will cause the rpm to dip down to 100 then pop back up while starting the car. It will cause the rpm to dip up and down while idling. It can also cause knocking while driving. I experienced all those symptoms when I adjusted the TPS position and the AAC valve position. You recently replaced the IACV so you'll need the ECM to relearn the air intake by temporarily unplugging the TPS:

Get the car warmed up with a 10 minute drive. With all accessories turned off stop the engine. Unlpug the TPS connector (brown). Start the engine back up and let it settle for a minute or two. If needed adjust the IACV screw to reach around 700rpm. Stop the engine then plug the TPS connector back in.

Dexter

THANKS A LOT!!!!

InfiniwhiptinitiII

iTrader: (1)

gosh i love it when that happens, good work fellas.

Br0nz

since no one has mentioned it clean your TB doesnt explain high speed probs but its good to do if never done before!

Maximum_Chaos_95

mine started doin the same but only under 2k rpms

Trini Boom

iTrader: (5)

The fuel injectors do not give you much warning when they are dying at all. I just did my valve covers including the rear and I ohmed out all my injectors at the same time. Four of them read 12.6 ohms while the other 2 read 11.8 ohms. Best believe that I changed them with some used ones I picked up for $50 for 6 with rail. Ohmed out those and they read 12.6 and replaced so that I don't have to go through that travesty of taking off the upper intake for a failed injector. Do it once, do it right!