My car starts good for 5 seconds then runs rough then good

M3GTR8

MEMBER
2007 JAGUAR X-TYPE
30,000 MILES

Hi,
previously I had an oil leakage and I fixed it.
after 2 weeks, car makes a popping sound and gone into limp mode,
replaced plugs and coils and cleaned injectors and throttle body and replaced throttle position sensor, checked battery and alternator.
it is out of limp mode, but, on first start in the morning, it runs rough for like 10 minutes, until temperature gauge reaches half (normal) and it runs fine for the rest of the day.
no check engine light.

6 Replies

HMAC300

MECHANIC
48,601 POSTS

Check for a vacuum leak, sounds like you have one and computer is richening mix up to compensate for it.

Was this

answer

helpful?

Yes

Thursday, April 12th, 2012 AT 10:34 PM

M3GTR8

MEMBER
6 POSTS

Thanks, and what is the best way to check for this?
Smoke machine? Carb cleaner? Or else?

SPONSORED LINKS

Was this

answer

helpful?

Yes

Friday, April 13th, 2012 AT 9:27 AM

HMAC300

MECHANIC
48,601 POSTS

You'll have to check all your hoses first like seeing if they are disconnected, holes, etc. Take car b cleaner and spray around intake, connections etc. But nnyou'll have to do it cold unless you find the problem first.

Was this

answer

helpful?

Yes

Friday, April 13th, 2012 AT 2:16 PM

M3GTR8

MEMBER
6 POSTS

No vaccum leaks found,
scan tools show p0300 (random misfire codes)
my check engine light doesn't work (even if I disconnect a sensor )
can you list me other possibilities to check for?

Was this

answer

helpful?

Yes

Friday, April 20th, 2012 AT 11:31 AM

HMAC300

MECHANIC
48,601 POSTS

If it's arandom misfire make sure to check your fuel pressure as it will cause this. It lshould be 46-55 lbs or 320-380 kpa if measuring metric. I am sassuming this is a gas vehicle not diesel.