Mr2 bogging/jerking

I have a 91 turbo. the last couple of days when driving the car before it warms up it seems to be bogging down and/or jerking. after the car warms up its all fine until i start to boost then around 2-4psi starts jerking agin then stops after in 4th and 5th gear. if i run at WOT through all the gears no jerking at all in 4th and 5th im guessing because turbo is already spooled up. any help would be appreciated

How old is your ignition?
I suspect it might be a good idea to do a tune up with new Toyota cap, rotor, wires and plugs.

Is the car modified at all?

What part of the country are you in?
The ECU limits the power of the engine if the ambient temps are too cold and also until the engine is up to temp.

rotor and cap have about 8 months on them. plugs and wires have about 6k miles. mods are the addition of a EBC/FCD set at 14.5psi T3/T4 turbo50trim K&N intake.

On a side note i tried to see if the AFM was on the fritz as per the BGB i checked the resistance between the pins... VS-E2 @ 338, VC-E2 @287, and THA-E2 was not constant i guess its because of the compression plate. i got readings but no consistant numbers i'd get a flash on the ohmmeter then it'd go to -1 move the compression plate it change up and down then after i stoped it it go back to 0/-1.

What plugs are you using and what gap?

bosh plat... i believe the gap is 32

I can almost 95% gaurantee this is your problem.

Bosch platinum are HORRIBLE plugs.
They work awesome in the turbo MR2 for LITERALLY 30 minute to an hour.

This is no joke. I've experienced it and seen other MR2s have the same problem.

Go buy yourself some NGK 6097s.
Order by part number, NOT by car.
Gap them to .028"

They are copper, so they will give you the best igntiion, but they wear fast, but they are cheap.
$1.65/each or so.

I would suggest changing them every 3000 miles with your oil.

Again, I can almost 95% gaurantee this is your problem.

Cold start injector maybe?

The new NGK 6097's did not clear up the bogging/jerking. Im open to more suggestions/tips for troubleshooting.

Are you using Toyota cap, rotor and wires?

Have you checked for codes?
I can walk you through this if you want.

Do you have an aftermarket BOV on the car?

What fuel are you using?

using toyota cap and wires... have not checked codes yet. i figured no codes if check engine light has not come on. help in that area would be appreciated. And OEM bpv is in place. and 93 gas

just checked engine codes.. bridged Te1 and E1 with paperclip.. steady blinking check engine light.

Steady flashing = good.

Has it been doing this for longer than one gas tank?
Could it be bad gas?

My last suggestion is check for boost/vac leaks.

Steady flashing = good.

Has it been doing this for longer than one gas tank?
Could it be bad gas?

My last suggestion is check for boost/vac leaks.
yes has been a couple tanks of gas. i've eliminated the EBC in hopes that the problem would go away. Just letting the Wastegate regulate boost. Same thing. then i hooked everythig back up took apart every connection between the MAF and turbo housing then reattached... same problem. all vac hoses i have tapped into i rechecked for possible cracks and no change.. i'll keep looking and researching thanks for the help so far.

When you have been touching the AFM/MAF, you never undid the two screws on the side of it did you?

The correct way to take that big wiring harness off of the AFM is the very thin C-clip.

If you undid those 2 screws, you damaged the AFM and that is most likely your problem :(

nope have not unscrewed the AFM. I did however check the AFM to see if that was the problem and it was not.

Thanks for all the help... it was a boost leak.. my hose going to the intercooler had a crack in it in the middle of the rubber hose. not on the ends like i had thought and checked. thanks again jecklandhyde. and all others that posted

whew ... long road to go down.
Glad you found it and I am glad you got rid of those Bosch Plats. ;)

seen other MR2's do very similar... bog down when cold round 1700rpm? does it keep doing it after it's warmed up?

Look at post #16 - the problem is resolved.

lol damn it. page 2!