My 98 Regal trembles @ 40mph

[LouK]

I just installed a new, not a junkyard or remand, icm (ignition control module) under the original coil packs. Checked spark continuity which is strong on all 3. I've rebuilt the trans, with professional help & installed a rebuilt 3.8l ohv long block with all new sensors. I'm not getting codes on my Autel AL519 but there is a yellow exclamation point and my cluster is showing "anti lock" & "brake" are lit up & go away. The shrtftb1s1 is steady at (0.0?) Any thoughts?

 

[MelsRegal]

Does it change if you go faster than 40 mph?
You are sure it's not wheel balance.
Does the 519 read ABS codes?

 

[LouK]

Does it change if you go faster than 40 mph?
You are sure it's not wheel balance.
Does the 519 read ABS codes?

It will intermittently studder/shudder over 40mph. I'm not sure if it's a wheel balance thing but, I think the shudder would be present at slow speed too. Yes it read ABS codes. I'm wondering if I've got a cracked/defective fuel injector.

 

[MelsRegal]

Have you done a fuel pressure test and observed after the car is shut off does the pressure drop too quickky?
You are sure it's not the transmission, lockup converter?

 

[LouK]

Have you done a fuel pressure test and observed after the car is shut off does the pressure drop too quickky?
You are sure it's not the transmission, lockup converter?

What would a quick drop in the fuel pressure indicate? I just installed a new fuel pump in the trunk. I installed all new electronics & hardware (minus wire pigtale) into the tyranny. Where is the lockup converter located again?

 

[MelsRegal]

A quick drop is a leaky injector.
The lockup converter is between the engine and transmission.

 

[LouK]

A quick drop is a leaky injector.
The lockup converter is between the engine and transmission.

I'll check these out & let you know what I've found. Thanks for the leads.

 

[HotZ28]

If you have an injector problem that is causing misfire & shudder under load, that should show up as a cylinder misfire on a scanner that is capable of reading individual cyl misfires. Does your scanner you have the capability to monitor that? If so, do a drive test with the scanner hooked up and watch the individual cyl misfires. It takes many misfires to set a hard CEL. Don't forget to check the CV joints for grease leaks and possible failure.

 

[LouK]

If you have an injector problem that is causing misfire & shudder under load, that should show up as a cylinder misfire on a scanner that is capable of reading individual cyl misfires. Does your scanner you have the capability to monitor that? If so, do a drive test with the scanner hooked up and watch the individual cyl misfires. It takes many misfires to set a hard CEL. Don't forget to check the CV joints for grease leaks and possible failure.

I don't know if my $90 Autel (AL519) can monitor the cylinders live. I'll look into that. I'll double check the CV half shafts but, they are only a year old. What did you think about the shrtftb1s1 reflecting a 0.0 reading? My fuel pressure gauge arrived today so, I'm going to see if pressure is maintained after shut off.

 

[G-914495]

Well, I found the problem about the shuddering issue. It was the (2) knock sensors. Both had excessive metal/rust particles interferring with communication with the ECM.