Lack of power in the morning?

[Afboy143]

Hey guys,
I’ve had this problem for a little while now, but I want to try to nip it in the butt. 4.0 SOHC V6 130k

In the mornings when I start it up, the truck hiccups a lot and lacks power. I constantly have to mash on the gas for her to start going. It hiccups a lot and sometimes even stalls out and I have to restart it. Once I get going, everything then goes fine and the truck drives normal. Any reason for this happening? It can’t be fuel related because I just replaced everything (gas tank, fuel pump, fuel filter, reflowed and cleaned injectors). Any ideas? Thanks!

 

[Brandon96]

What do you mean hiccups?

Also, sometimes an non fuel-related loss of power is because of clogged / bad cats. An easy test would be to disconnect your y-pipe and take a quick open header run to see if all your power comes back. It's something easy and worth trying

 

[Afboy143]

I wish I had a video of it!

Well, when I put it into reverse, it put-puts backwards. Sometimes it’ll even stall out. Then when I get the truck in drive, it’ll putt-putt forward. I’ll mash the gas, but it’ll only rev up to about 3k rpms, but it’ll putt-putt. After a good 20 seconds of this, the truck finally gains momentum and it starts going like it should with no problems. I have a feeling the cold weather has something to do with it too since it’s been so cold here lately (well it was 50 today, cold for us Floridians!)

Also, it can’t be the cats. I don’t have any … BUT I did put on a magnaflow hi-flow cat yesterday to help dampen the noise for the new daughter. This problem existed before the cat install.

 

[Brandon96]

aah, Touché on the cats : I don't know as much about the OHC's as I do the OHV, but I did know a clogged exhaust system definitely kills or bogs down an OHC engine big time.

Have you checked/cleaned your MAF and IAC sensors? Plugs/wires? Does it sound like it could be a cylinder just not firing? I think those would be the next things to investigate, along with your coil pack.

P.S. - Can I get a part# from you sometime on your AMSOIL filter? My K&N just got smashed by my stupidity during this engine swap lol.. I'm almost fairly certain that it's the same 3in opening right? :scratch:

 

[Afboy143]

aah, Touché on the cats : I don't know as much about the OHC's as I do the OHV, but I did know a clogged exhaust system definitely kills or bogs down an OHC engine big time.

Have you checked/cleaned your MAF and IAC sensors? Plugs/wires? Does it sound like it could be a cylinder just not firing? I think those would be the next things to investigate, along with your coil pack.

P.S. - Can I get a part# from you sometime on your AMSOIL filter? My K&N just got smashed by my stupidity during this engine swap lol.. I can't justify spending another $60 bucks on one

Oh I bet! I custom built my exhaust from the manifolds back so I know it's in good working order!

MAF has been cleaned yesterday. Where is the IAC sensors? Plugs and wires are new. How can I check if a cylinder isn't firing? Don't think that could be it because it pans out and smooths our eventually. Coil pack is original- something I could check

AMSoil filter ran me about $75 but it's 100% worth it! Amazing filter. I could def tell a difference with it over a K&N and others I ran. Ill get you a number when I get home. At work now

 

[Brandon96]

Well with your exhaust (I too have a 2.5in dual setup), start it up and if it's doing it's thing walk around the back and listen to it, it'll sound like it's coughing or you'll be able to notice a 'rushing air' sound whenever that cylinder doesn't fire.

Your IAC sits on top of the upper intake plenum and should resemble, but may not look exactly like mine (OHV V6). It is used to help the engine keep it's Idle speed up while your in park, BUT I THINK I read somewhere that it is used while driving, or under throttle conditions while your in open loop, but isn't when the truck enters closed loop (or 'warms up') which might be why your truck straightens itself out.. but don't quote me, I read it once. A good clean might, just MIGHT help.

The reason I suggested the coil pack is because my OEM one actually was burning up my #5 wire for some reason, about ever 2000 miles. I don't know of any methods to check the condition of a coil pack, but if your truck IS possibly be missing on one cylinder, it could be the reason. I had 145k on mine when I had to replace it.

 

[my98nnj]

Check the engine coolant temperature sensor. Make sure it's within spec especially when it's cold. Think of that sensor as the "choke".

 

[Afboy143]

Well with your exhaust (I too have a 2.5in dual setup), start it up and if it's doing it's thing walk around the back and listen to it, it'll sound like it's coughing or you'll be able to notice a 'rushing air' sound whenever that cylinder doesn't fire.

Your IAC sits on top of the upper intake plenum and should resemble, but may not look exactly like mine (OHV V6). It is used to help the engine keep it's Idle speed up while your in park, BUT I THINK I read somewhere that it is used while driving, or under throttle conditions while your in open loop, but isn't when the truck enters closed loop (or 'warms up') which might be why your truck straightens itself out..

The reason I suggested the coil pack is because my OEM one actually was burning up my #5 wire for some reason, about ever 2000 miles. I don't know of any methods to check the condition of a coil pack, but if your truck IS possibly be missing on one cylinder, it could be the reason. I had 145k on mine when I had to replace it.

Interesting, and I have replaced the IAC before. I just didn't know where the IAC sensor was for me to clean it.

As for a cylinder not firing, wouldn't that throw a code? Cylinder so and so misfire?

 

[Afboy143]

Check the engine coolant temperature sensor. Make sure it's within spec especially when it's cold. Think of that sensor as the "choke".

Can you elaborate on this please sir? Where is it at and how do I make sure it's in spec? I do know the guage on the dash works fine.

 

[Brandon96]

Interesting, and I have replaced the IAC before. I just didn't know where the IAC sensor was for me to clean it.

As for a cylinder not firing, wouldn't that throw a code? Cylinder so and so misfire?

Oh, well it shouldn't be the IAC then. (For future reference, you take the sensor off and it has two holes in it, you can spray the crap out of the insides with sensor cleaner to clean it )

To answer your question, I don't know. I worked on an Explorer, same engine different year, that was backfiring through the intake, that threw all types of missfire codes, However my PCM did NOT pick up when my spark plug wasn't detonating the gas in the cylinder, but it would pick it up if I took the wire off the plug, it's odd, and I don't know how to explain that, lol.

If it's not your plugs/wires or coil pack, and your sure all your sensors are within spec, I'm fresh out of ideas,

 

[Afboy143]

Oh, well it shouldn't be the IAC then. (For future reference, you take the sensor off and it has two holes in it, you can spray the crap out of the insides with sensor cleaner to clean it )

To answer your question, I don't know. I worked on an Explorer, same engine different year, that was backfiring through the intake, that threw all types of missfire codes, However my PCM did NOT pick up when my spark plug wasn't detonating the gas in the cylinder, but it would pick it up if I took the wire off the plug, it's odd, and I don't know how to explain that, lol.

If it's not your plugs/wires or coil pack, and your sure all your sensors are within spec, I'm fresh out of ideas,

Well I guess it wouldn't hurt to clean the sensor atleast! MAF cleaner or just carb/choke cleaner? I appreciate all your ideas!!

 

[96eb96]

intake gaskets? very common issue. They warm up and seal.

 

[Afboy143]

intake gaskets? very common issue. They warm up and seal.

You mean the upper and lower intake gaskets? I replaced the upper gaskets when I replaced my injectors with reflowed ones over the weekend. Should I have replaced the lower as well?

After reading everything, I am leaning toward a bad IAC.

I ran to KFC for lunch at work. While I gassed the truck a bit to inch up, it stalled out. I started it up, stalled. Started it up, and went. How embarrassing.

 

[ranger7ltr]

I am gonna ask...

About the fuel pressure? Can you attach a gauge to see what the pressure is doing while driving? Also do you have a vacuum gauge to attach to see what thevacuum levels are?

Sounds like the IAC could be bad but I am thinking the fuel is lean and/or there is a vacuum leak in the intake tract...

 

[swetrid]

Intake gaskets

 

[SDR]

I had the same problem and though it was the gaskets too but after a lot of reading figured out that the engine coolant temp sensor is another cause for it. There is 2 of them on the engine directly behind the thermostat. One is for the temperature gauge and the other one is for the cold start information for the computer to process for timing and fuel flow. This is the grey one that needs to be replaced not the black one.

 

[joe doe]

are you losing antifreeze?have you checked?if your losing antifreeze and dont know where its going then you may have a cracked head .symptoms sound like typical cracked head .

i have a cracked head on the drivers side .when i first start my 2000 sport it will idle funny for 30 seconds or so then smooth out .
whats happening here is overnight or any long sit allows enough antifreeze to enter a given cylinder ,enough to foul it out for awhile until the antifreeze is burned off.
then after that it will run and idle fine until the next start .

sound familiar??if so check your radiator level and see if your losing any.

getting any misfire codes?

 

[BOWLING91]

i would for sure check ect. mine would act up when cold out and would stutter or hiccup like your talking about, and it would not want to run when it was really hot cause the motor did not know what temperature it was at. the ect is like a choke fora fuel injected car. it tells the motor you need lots of fuel when it is cold to keep it running like whata choke does. mine would die when i put it in drive too.

 

[SDR]

i would for sure check ect. mine would act up when cold out and would stutter or hiccup like your talking about, and it would not want to run when it was really hot cause the motor did not know what temperature it was at. the ect is like a choke fora fuel injected car. it tells the motor you need lots of fuel when it is cold to keep it running like whata choke does. mine would die when i put it in drive too.

Exactly. Great way to describe what the ECT does.

 

[BOWLING91]

the idle air control valve controls the motor at idle when your ac compressor kicks on or when there is a load on the engine. trys to keep it idling the same