03 2v Lethargic

[wmfateam]

2003 GT, had just replaced the fuel pump, cleaned injectors, new plugs and a couple coils(NGK coils) that were broken when swapping intake manifold. Car was running fine, sounded/felt very healthy. Then last week after a month or so of driving fine, I started it up, it fired right up and then the exhaust note changed like an electronic exhaust flap closed. AKA like it went a little quieter. Not the sound of the idle coming down after a cold start, but like the engine was trying to move through sand. Like lethargic. Then when driving has that same feeling as it is driving to drive through sand or uphill.

I have shit skills/knowledge when it comes to engine diagnosis so I am reaching out as I start to dig into it and asking for any suggestions or directions in which to test. When hooked up to a scanner that can monitor live data, there is no misfires, no codes except for the fact I have no cats, fuel pressure is high 30's.

 

[RAU03MACH]

Hows the throttle body look inside

 

[96blak54]

Oil change lately? Check engine light?

 

[wmfateam]

Hows the throttle body look inside

Completely clean. Sonic cleaned 100 miles ago.

 

[wmfateam]

Oil change lately? Check engine light?

No check engine light, no present codes and no pending codes. Oil has been changed twice in last 100 miles as it was motor swapped 100 miles ago and I am just trying to make sure it is clean inside. Explorer 2v with Mustang PI intake and long tubes.

 

[SnakeBit!]

no cats and have long tubes....is there any kind of tune in the car to account for those mods?

 

[RAU03MACH]

timing is good a tooth or 2 off will affect performance

 

[96blak54]

Especially is the engine was rotated counter clockwise(perspective from the engine front) when installing trans. The crank sprocket will jump a tooth

Also I found oil types like "high milage" type oil will cause the lifters to over react and kill rpm performance. Strictly 5w-20/5w-30 synthetic only. No "high milage" branded oil

 

[wmfateam]

no cats and have long tubes....is there any kind of tune in the car to account for those mods?

Factory untouched ECU that was running perfectly fine for 100 miles, about a month of short drives around an industrial park.

 

[wmfateam]

timing is good a tooth or 2 off will affect performance

I can check it, but do these motors ever have the timing jump after running fine for a month? I'm used to timing belts personally.

 

[wmfateam]

Especially is the engine was rotated counter clockwise(perspective from the engine front) when installing trans. The crank sprocket will jump a tooth

Also I found oil types like "high milage" type oil will cause the lifters to over react and kill rpm performance. Strictly 5w-20/5w-30 synthetic only. No "high milage" branded oil

It does have Valvoline synthetic high mileage in it right now. I'll give it a couple oil changes with standard synthetic and get it hot in between changes. I appreciate that. The high mileage was on sale and I just bought the cheapest name brand synthetic oil since I was going to be changing it multiple times.

 

[RAU03MACH]

I can check it, but do these motors every have the timing jump after running fine for a month? I'm used to timing belts personally.

So when I did the cobra engine there was 150 thousand miles
The chains were loose on the sprockets
As mentioned by black if you were to turn the engine counterclockwise it lossens up more
And chains can jump a tooth or more
Something to think about
I am going to do the ones in the truck I just picked up
Just to be on the safe side the whole kit

 

[wmfateam]

So when I did the cobra engine there was 150 thousand miles
The chains were loose on the sprockets
As mentioned by black if you were to turn the engine counterclockwise it lossens up more
And chains can jump a tooth or more
Something to think about
I am going to do the ones in the truck I just picked up
Just to be on the safe side the whole kit

Shit, I've never thought to turn the engine when installing a trans. I feel like that is more work to get back out from under the car instead of just turning the driveshaft in the trans. I'll start with the oil change and then pull the valve covers off while the crank is at top dead center. Thank you for your input!

 

[96blak54]

I did the exact same thing with one of my builds. It went from strong, high rev to WTF happened!!! and that was after I did a 500mile oil change to some high mileage Castrol..... that was on sale. My best analysis?......oil weight has direct effect to the lash adjusters. Thicker oil will pump them up. Not a bad thing on the intake adjusters, but the exhaust pumping up will kill rpm. Opening the exhaust valve early is a direct effect to rpm and hp

 

[SnakeBit!]

I will still say, no cats and long tubes, the ECU is not getting the proper information for the air fuel mixture. I'm surprised it has not thrown a code. That might be an issue since it should be so maybe there is an issue with the ECU.

 

[RAU03MACH]

i have seen a lot of people running long tube no cats no tune
the cars run fairly strong
i personally cant tell difference between long tube and short headers its same to me

 

[wmfateam]

I did the exact same thing with one of my builds. It went from strong, high rev to WTF happened!!! and that was after I did a 500mile oil change to some high mileage Castrol..... that was on sale. My best analysis?......oil weight has direct effect to the lash adjusters. Thicker oil will pump them up. Not a bad thing on the intake adjusters, but the exhaust pumping up will kill rpm. Opening the exhaust valve early is a direct effect to rpm and hp

Dude, changed the oil to standard 5w-20 Castrol GTX Synthetic and it is right back to normal. THANK YOU SO MUCH FOR BRINGING THAT UP!!!! Drove it around and was so excited that I forgot I needed brakes still and had a "fun" test drive, lol.

 

[96blak54]

Glad it was a simple fix. Now if you really want the fun to begin, go find some old pre95 lashers, replace them on exhaust valves. Might be a little noisy at idle tho.

 

[96blak54]

Not many know how the lashers function. They simply think the lasher take up gaps with the followers to the valve. Actually, they do take up gaps and keep things tight, but also have a character with oil pressures and opening points from the cam lobe. In short, the lashers only receive 15 psi of oil and thats at high rpm. in the single digits at low rpm. It doesnt take much oil psi to over actuate the lashers and a heavier oil will do such a thing. This causes the lasher to over act and change the valve timing. Our big cam lobes and follower valve system design was ment to be a variable valve timing. If you do feel frogging and want to test this, swap out the exhaust lashers for earlier 10w30 style. Youll pick up power and rpm