Car runs like Crap

M

Mel96GT

New Member

Aug 31, 2004

255

1

0

San Diego

Dec 22, 2010

#1

• Dec 22, 2010

• #1

Hey guys, Been out for a while. Need your expertise. I returned My 96 GT to stock (NPI cams, NPI intake, stock tune) since I am selling it to a friend and that is how he wanted it. Now it runs awful, it will idle fine but at 2800+ rpm's it really struggles to get moving but there are no DTC's showing. What are your suggestions? I hope I didn"t skip a tooth on a cam, but I was very careful. Thanks in advance.

 

joshjwc9

Active Member

Jun 12, 2006

1,095

17

39

Palm Harbor, FL

Dec 22, 2010

#2

• Dec 22, 2010

• #2

When was the Fuel Filter changed? How about spark plugs?

Try resetting the battery for it to learn the new or old trim values too.

I am sure some better know-it-all's will chime in soon too.

 

mustang_matt

New Member

Oct 8, 2010

29

0

0

TEXAS

Dec 28, 2010

#3

• Dec 28, 2010

• #3

sounds like a timing thing to me. Maybe not advancing. Is the pip/spout in? Or check the harness grounds. Bad grounds can cause all kinds of weird issues

 

wmburns

SN Certified Technician

Aug 14, 2009

5,892

514

204

Houston Texas

Dec 28, 2010

#4

• Dec 28, 2010

• #4

Check the base motor. Perform a compression test and cylinder leak down test.

Check for correct fuel pressure.

OBTW, 96+ don't have a pip/spout. Advance is completely controled by the PCM.

 

nyuk98gt

15 Year Member

Oct 10, 2000

1,427

6

79

Chesterfield, MO

Dec 28, 2010

#5

• Dec 28, 2010

• #5

Mel96GT:

In addition to the other good suggestions given, I'll add one more (may or may not be a good one). Check that the plug boots have not slid down on the wires. When this happens the wire clips are not fully contacting the plugs and the engine will run poorly. Use an old plug to test fit each boot/wire. The boots slide up and down on the wires. Be careful not to bend/break a wire as you adjust the boot. The other thing to check is that each wire is giving about the same "ohms/foot": check resistance and divide by total length for each wire.

HTH,

Chris

 

M

Mel96GT

New Member

Aug 31, 2004

255

1

0

San Diego

Jan 2, 2011

#6

• Jan 2, 2011

• #6

All solved!! The plugs had some water and oil and after blowing the water and oil out and the car ran MUCH better. That was it now the car runs fine. I'm surprised how much decent torque the NPI has at low rpm's. Still a slug tho! Thanks guys it shows how important it is to keep those plugs dry!!!

 

nyuk98gt

15 Year Member

Oct 10, 2000

1,427

6

79

Chesterfield, MO

Jan 2, 2011

#7

• Jan 2, 2011

• #7

Mel96GT:

Thanks for the update. This will help others who have rough-running engines. Good work getting Old Paint running well.

Chris

 

Eleanor's Girl

Member

Feb 22, 2009

49

0

6

Denton, Texas

Jan 4, 2011

#8

• Jan 4, 2011

• #8

This was very helpful 'cause my car runs crappy too! I plan to just replace my plugs though.