SW20 with Lumpy Power & Flat Spots

This section is for technical Q & A
Please try the search function before starting a new thread.
Forum rules
Many subjects will have been discussed before. Please try the search function before starting a new thread.
Check in the Know Your 2 as the information you need may already be there.
Important ! - Please make your topic title as descriptive as possible . titles with just "help" generally dont get as many answers as a title that points to the problem
Post Reply

Topic author
Posts: 10
Joined: 09/05/19 10:46
Years of MR2 Ownership: 1
MR2's Owned: 1
Location: Eastleigh, Hampshire, UK

SW20 with Lumpy Power & Flat Spots

Post by ToyotaTom »

Hey All,

I have a 1995 NA MR2 that has started having lumpy power under accelerating, particularly when cold. This also creates flat spots in performance around 3000 RPM, again more so when cold.

No engine codes are being shown and it does get better when it gets warmer. I have also found if you remove the EFI/ECU fuses the problem goes away for a while. Any ideas?

Thanks :)

User avatar

Full Member
Full Member
Posts: 859
Joined: 29/01/11 18:53
Gender: Male
Years of MR2 Ownership: 9
MR2's Owned: 1
Real Name: Jan Olsson
Location: Leicester

Re: SW20 with Lumpy Power & Flat Spots

Post by abovetherim »

Check coil pack for cracks. Check dizzy cap and rotor for wear and deposits. Check plugs gap and condition.

Also when was last fuel filter change?
Read the resistance of the ect sensor at different engine temps to check that is working.

Could be bogging when cold due to weak spark not being able to cope with extra fuel for cold running.
Could be not getting fuel for cold running because of a blocked filter or ect not registering cold.

A few things to check before throwing parts at it.
1991 rev 1 T Bar n/a 3sge import. A work in progress!!!

Post Reply

Return to “MK2”