Detonation/Misfire at no/low boost!

[one320b]

I've had my turbo system in and running on my '03 ES for about 30K miles now..all has been well..running a mere 6psi. One day last week, I got a bad knock when accelerating ...car was at around 2psi or so below 4K RPM...it feels like detonation, but no backfire/noise/etc..so more like a misfire then anything. Currently don't have a wide-band hooked up so unsure as to whether it is fuel or ignition related. My ideas are that, my ignition wires/spark plugs or coil pack(s) are going bad, MAF is dying or is bad, or maybe fuel pump. The car should not be having fuel problems...nothing has changed in the last 30K and I've had the car on the dyno, made numerous runs, etc...at 6-7psi and never one knock or anything... what are your thoughts on this?

 

[one320b]

I've had my turbo system in and running on my '03 ES for about 30K miles now..all has been well..running a mere 6psi. One day last week, I got a bad knock when accelerating ...car was at around 2psi or so below 4K RPM...it feels like detonation, but no backfire/noise/etc..so more like a misfire then anything. Currently don't have a wide-band hooked up so unsure as to whether it is fuel or ignition related. My ideas are that, my ignition wires/spark plugs or coil pack(s) are going bad, MAF is dying or is bad, or maybe fuel pump. The car should not be having fuel problems...nothing has changed in the last 30K and I've had the car on the dyno, made numerous runs, etc...at 6-7psi and never one knock or anything... what are your thoughts on this?

I should also mention that it still does this, it wasnt a one time thing..and it now does it in every gear but first...the second i floor, or attempt to floor, the car it bucks, etc...also when idling for a while(idle is smooth btw) and i go to take off..the car bogs, runs like s***...not sure what the deal is..but I'm leaning towards bad spark plug wires..thinking that maybe one of the plugs isnt firing right and is filling the cylinder w/ fuel causing over rich condition during initial acceleration...

 

[PaulMP3]

what are you using for fuel/ignition tuning? What turbo kit do you have?

 

[THEGOLDPRO]

mine did the same thing, i changed the plugs, and it cleared right up.

 

[mp5smuggler]

im having the same trouble but im having a start up issue where it wants to stumble and stall till its warmed up. then i thrw a code saying misfire in cyl 3. ive got a new set of plug wires coming in and ill throw some new plugs in it too. i really hope this is the solution cause if not i think its going to get very expensive.

 

[one320b]

I'm going to get some new plug wires and plugs to see if that fixes the problem..I'm hoping it does..the plugs only have 6-10k on them, but are cheapies, so we'll see...

 

[bazooka joe]

update, anyone?

 

[one320b]

I haven't swapped my plugs/wires yet...some time w/ in the next week..been so busy. It's really irratating though..like, I can get up to 2-3psi if a gradually go there...but if I try to floor the car, it'll misfire as the turbo spools...not even at 1psi yet! I'm going to go through a battery of new parts to solve the issue...

-Spark plugs
-Ignition Wires
-Fuel Pump(upgrading anyways)
-FPR(upgrading anyways)
-Fuel filter
-MAF

I've also got the FM o2 clamp, i can still hear it clicking away when the turbo spools or when I'm under pressure, so I don't think that got disconnected..

Anybody know off hand where I can get info on testing the MAF? I just need to know what numbers it should put out, etc when I test it?