Strange ignition issue?

[jessicas gst]

Hello, I have a weird problem maybe someone knows the answer to.

I have a 96 with a 6bolt with a 2nd gen head 16g and it runs great... But if its on the interstate cruising at 75-80 after a min or 2 the exhaust note will change slightly and if i give it more gas it wont have any power.
I then have to let the rpms drop to idle then its fine again until i get back up to speed then it will do it again after a few min.
It feels like a plug stops firing. I have new plugs so its not that, perhaps coil pack? wires?
Or an issue from the 6bolt with the 2nd gen head?

I bought the car 5 months ago from a guy that really had no idea what he was doing so it could be anything really but before i start replacing parts perhaps someone here has had the same problem or maybe its a common problem.

Thanks.

 

[fourreGsixty3]

Does it only happen when you stay at a consistant speed of 75mph, or if your accelerating past that, but it just wont go?

What plugs are you using, and what are they gapped to?

I as well as MANY others on here have found that the NGK BPR7es' work great for slightly modded DSMs. The gap should be between .028"-.032". Verify the gap for us please.

You could try gapping it tighter to a .026" to see if that fix's it. If that fix's the problem, then I would visualy inspect the wires for pin holes with white burn marks on the wires, you could also try reving up the engine at night, and watching to see if arcing is comming out of the wires. Also try salt water in a mister bottle, and mist the plug wires with the salt water, the salt water is an excelent conductor of electricity. If the wires inspect fine, then I would check the out put from the coil, or try another coil from a friend, or grab out for cheap from a junk yard.

Also what do you mean that the exhaust tone changes? What does it sound like after it changes? Is there blackish smoke comming out of the exhaust?
Does the car feel like its hesitant when you try to accelerate?

It could be multiple small problems that mask together to make ONE noticable problem.
An example could be that the coil isnt putting out enough voltage, and then the spark isnt strong enough to jump to the ground electrode, thus causing a misfire which over loads the cat with fuel, and slowly melts it, and plugs it up. I repeat that this is just an example...but a possibility

 

[romeen]

Your problem sounds more like it may be fuel related. Your profile shows you have intake/turbo/exhaust upgrades but no mention of fuel system upgrades. If that's the case then that could be your problem. Also do you know if the fuel filter has ever been changed? Your fuel pump could also be on it's way out.

 

[jessicas gst]

its not fuel related.
Plugs are bkr7e gapped .28 IIRC.

It happens only at a constant steady cruise at 80.
The tone sounds like it goes from a 4 cyl to a 3 cyl.

The car pulls hard with no issues except holding steady at 80.

 

[fourreGsixty3]

Romeen does have a good point. How are you sure its not fuel related?

Also I hope that it was a typo that you gapped it to .28"... because it should be .028"

What are you boost levels at? Because with the mods you have you should have fuel mods. You could get away with a Wally 190lph fuel pump if your at stock boost.

 

[92awddsm]

Do you have dsmlink? Which cas are you using, green top or black top? Do you have the pot mod? Do you ever get a cel when it happens? Sounds like the typical random misfire that 2g's suffer from with a 6 bolt swap and no dsmlink.

 

[fourreGsixty3]

That is definately a possibility. But she said it only happens at a steady 80mph, but who knows something about staying at 80mph could just be the perfect "random" spot.

 

[92awddsm]

That is definately a possibility. But she said it only happens at a steady 80mph, but who knows something about staying at 80mph could just be the perfect "random" spot.

Im just guessing that is what the problem is because it happens under steady cruise and not when under a load like accelerating. It may happen at lower speeds but she probably doesnt drive that slow to find out.

 

[jessicas gst]

I dont know what cas is being used.
How would i find out?
Yes i have a cel constantly on. the PO said it was from the cas random misfire.
How do i fix this problem?

 

[jessicas gst]

Unplugged the TPS and problem solved!
Car still runs great so i guess i will just leave it unplugged.
Thanks for the replies.

 

[assault187]

Unplugged the TPS?....My plug popped off the TPS before and I couldnt even drive the car. There was NO fuel when I would atempt to accelerate from a stop, couldnt even get the car to 5 mph. The ECU takes in alot of info to calculate a "misfire" including barometric pressure. Some people eliminate the ECU from seeing the barometric pressure sensor from reading over 76 Kpa by adding resistance so the ECU thinks the value is lower then it actually is. This is the "POTMOD".