Hey all - been a while since i've checked out this forum but it's also been a while since i've had a problem with the "silver bullet". Anyways - my first issue is after the car has warmed up a little bit, in low RPM and more than usual gas (such as turning onto a main road out of my neighborhood), the thing just sputters and goes nowhere. I've almost gotten hit several times because of this now. Even under moderate acceleration it still does this. I replaced the plugs, plug wires, and just replaced the front valve cover gasket (when i replaced the sparkplug wires they had a fair amount of oil on them when i pulled them out).

After replacing the front gasket, i took it for a spin and the behavior has not improved one bit. I'm about to peel off the intake manifold to get a look at the back half. Would improperly gapped spark plugs cause this? I'm about to recheck my gaps. I pretty sure my haynes manual says 0.028 or 0.03. I will double check that as well.

Another issue with ignition is in the high rpm > 5.5k. Again, before it warms up i do not experience this behavior. After about 5 - 10 minutes of running, I can't even hit the rev limiter. It pops and backfires like crazy. Replacing the spark plugs/wires did not help this either.


On another note, on particularly cold mornings (this has happened 3 times this week while leaving to go to class), I back out of my driveway, put it in drive, and it can take 5-10 seconds to actually engage. A few weeks before i noticed the transmission "slipped" into 2nd gear randomly (cruising at about 40mph), but then went back to 3rd, 4th, OD like normal. The latter reminds me of when i had to spend 2 grand for a transmission rebuild due to the transmission going into LIMP mode. It hasn't done that recently, just the failure to engage to drive immediately.

Thoughts? Much appreciated. By the way, I said '98 sport in the title, but if you guys didn't catch this - it's the v6 2.5L auto.

 

I'm having the same kind of symptoms. I can't hardly accelerate and feels like the motor is very restricted and backfires occasionally...a mechanic at the shop I worked at recommended that I look at the exhaust system (which I have yet to do, but will shortly!) to see if the system is plugged up. My car also runs fine when cold, but the instant it warms up, it's all fussy. I also changed the wires and plugs, still no improvement...

So my advice is look to your exhaust system! That's my next move!

Good luck on the hunt, I'll update if I find anything else out...

 

from 2k-5.5k the powerband is normal and pulls regularly. anything after 5.5k to 6k the motor has no power and makes popping noises.

the low-rpm sputtering is intermittant and doesn't always occur.

exhaust system is wide open - no catalytic converter and a flowmaster 40 muffler.

 

You say you have replaced plugs wire ... Have you replaced the cap /rotor ???

 

LOL! Yeah I caught that when you said front valve cover. I thought with the V6's you had to pull the intake plenum to replace the rear sparks plugs, think maybe an intake leak but don't quote me on that since. I would also get a back pressure test done on your exhaust system.

Hows does your transmission fluid look? Is it still red, does it have a kinda skunk smell to it, is the fluid level within spec?

 

Don't forget about the o2 sensors.
Does your car(s) (both who are having similar issues) drive fine when at speed, such as an interstate or highway? Does this only happen when accelerating from a stop?

 

OCCASIONALLY from a stop. drives fine at cruising, and only spits and sputters at 5.5k+ RPM. the high RPM issues only occur after about 5 to 10 minutes of running.

i havent had any transmission issues for a few days so as of right now i'm just concerned about the ignition problems.

i have no CEL by the way.

 

i jinxed myself. on the way to class today i threw a CEL, had odd transmission behavior and now the transmission is stuck in 2nd gear.

sounds like another rebuild. i may just part the whole thing out. it's not worth the metal it's made out of in my opinion. 2 years ago I had the same thing and it costed me 2 grand for a rebuild.

anyone want parts or a '98 v6 avenger with a bad transmission?

 

shelled out another 2 grand for a rebuilt transmission, and i'm back on the road.

as far as the bogging in low rpm/no power at high rpm - add the fuel filter to the list of things i've tried. again, no help. i may have better fuel economy but it's still behaving erratically.

any ideas? i'm about to run out of things to try.

 

Never answered me