Help with ailing LS

[1sicklx]

I've replaced the plugs and the #5 coil pack as well as the valve cover gaskets as oil was leaking into some of the plug wells.

Driving the car it gets "jerky" on inclines and continues when stopped at a traffic light.

At times the power just doesn't seem to be making it to the wheels during all this.

Transmission? Torque Converter? Computer?

I reset the computer after swapping out the ignition parts and it's throwing a code (check engine light). I'm going to have it read at lunch.

[rtusnake]

Waits for code...

[1sicklx]

BTW, these symtoms were present before plugs and coil pack were replaced.

Did the plugs because they were due and the coil because it had went south.

[banditmwp]

replace all the coil boots

[QWKSNKE]

yeah, I am thinking boots as well

[1sicklx]

Code is for ignition coil malfunction.

Picking up the new boots today.

[93cobra1928]

Be liberal with the dielectric grease.

[SvoBrown]

The ls is a great looking car. Replace everything.

[1sicklx]

After valve cover gaskets, coil boots, and two coil packs;

Survey says ....

replace the computer.

Codes previously thrown ...

p0606 - PCM / ECM Processor fault
p0308 - Cylinder 8 misfire detected
p0316 - misfire detected on startup (first 1000 rev)
p0358 - Ignition Coil H Primary/Secondary Circuit malfunction

These were pulled after coil 5 and valve-cover gaskets were replaced.

After replacing coil 8 and the remaining coil boots I reset the computer and saw marginal improvement. Engine light was off for about 200 miles, but it still wasn't right (no torque, higher rpm to maintain speed, didn't sound right under load).

Yesterday, engine light comes back on and starts flashing (again) and now it's difficult to pickup or maintain speed, still sounds off, and has started missing at idle and under load.

No oil has leaked into the sparkplug wells since replacing the gaskets.

Any thoughts?

[BIGDATOWN]

Depending on what the code is now, the lack of spark and bad running condition could have clogged up your converters.

[Craig K.]

egr stuck open? sounds like a similiar running condition that we had with the Durango.

How many miles, should you just all coil packs, wires/plugs?

[1sicklx]

105K

Plugs are new. There are no plug wires.

[1sicklx]

After going into fail safe mode I took it to a shop. They've had it 3 days and can't figure out what's going on.

Dropped the exhaust from the manifolds back and saw no improvement so they don't think the cats are at fault.

The ecu hasn't thrown any new codes, but it is now missing on cyl 4. checked the coil, plug, injector, fuel pressure, wiring, cyl pressure ... good spark and fuel, cyl pressure within normal tollerances ... moved the coil, plug, injector to a different cyl and #4 is still missing. They don't know what's causing it.

Throttle is not responding, but the IAC seems to be functioning as they can adjust the idle through the ecu.

:banghead:

[QWKSNKE]

I wonder if you have some injectors going out. Can you slap some 19's out of mustang to throw in it to see if that resolves the issue?

[banditmwp]

:shrug:

Broken valve spring?

[QWKSNKE]

:shrug:

Broken valve spring?

spring or follower was my next guess

[swammi]

just ran into similar issues with a 4.6 crown vic at the shop. i replace the crank sensor and this took the 1600 code out. after more checking it was a valve sticking . does it run better cold ?

[ncontt]

:shrug:

Broken valve spring?

had a buddy with broken valve spring on a 99 gt....sounded similar to these symptoms :shrug:

[banditmwp]

had a buddy with broken valve spring on a 99 gt....sounded similar to these symptoms :shrug:

can't remember if it was qwk or italian lx but one of them had similar symptoms from a broken spring..

[EHardy1971]

can't remember if it was qwk or italian lx but one of them had similar symptoms from a broken spring..
Italian. Have you tried a compression/leakdown test on it?

[1sicklx]

They did a compression test on every cylinder and all were within normal tolerances.

The first shop has given up. Now I'm trying to decide what to do ... I talked to the service department at the local ford dealer and told them everything that has been going on. They believe the computer may still be the root cause, but of course without looking at it he can't be sure. They offered to diagnose it for $70 ...

One thing the first shop did mention was there's a rattling sound coming from the valvetrain when the engine is cold, but they could not find where it was coming from nor any damaged parts. (problem #2?)

Another thing the first shop mentioned was while monitoring the TPS it was not giving accurate readings when applying the throttle. Was told by the ford service manager this could also be attributed to the computer.