Miss like it hits a brick wall at 4000 RPM

[JoroCorona]

I'm doubting its ignition. It soulds like the car thinks its in a different gear. But you said you replaced the PRNDL switch. Have you tried the Park Neutral Saftey Switch?

[slick]

I'm doubting its ignition. It soulds like the car thinks its in a different gear. But you said you replaced the PRNDL switch. Have you tried the Park Neutral Saftey Switch?

 

Not yet, mainly because I have not recieved a definate answer on where that is located. I keep wanting to say it's underneath the shifter maybe?

 

EDIT- After looking at my Haynes Manual, the park Neutral switch is what I have replaced. So, where is the PRNDL switch at then?

[JoroCorona]

Well, your using the same manual as I am... So if you don't know neither do it.

[slick]

I should have a VSS coming in a few days, and Tony(5speedz34) is gonna bring me a set of coils and ICM, so I'll give all that a shot too.

[5speedz34]

Ok, cool I'll go look in my garage tonight for them.

[jeremy]

I would doubt the VSS is the culprit, but I could be wrong.........hopefully either that or the coils/ICM will fix your problem though...

[4spdz34]

if the car though it was in the wrong gear, the computer would command that gear no matter what postion the prndl is in. also the car has a 7150 rev limiter in every gear and even if it didnt a 3.4 car has a rev limit of 6500 when rolling in neutral above 25 mph. there are only to things that can cause this problem, ignition or fuel, we have checked the fuel pressure, and it is impossible two check fuel volume while driving. its in the ignition or its subsystems. but just for shits, slick does your fuel gauge have that pressure relief valve on it with a clear hose? if so when the car is idleing go ahead and hold that valve and see if the car stalls. if it does you need a pump. you can check the resistance of each wire by ohming from one end to the other of the wire, also check for carbon inside of the spark plug boots or for rust.

[slick]

if the car though it was in the wrong gear, the computer would command that gear no matter what postion the prndl is in. also the car has a 7150 rev limiter in every gear and even if it didnt a 3.4 car has a rev limit of 6500 when rolling in neutral above 25 mph. there are only to things that can cause this problem, ignition or fuel, we have checked the fuel pressure, and it is impossible two check fuel volume while driving. its in the ignition or its subsystems. but just for shits, slick does your fuel gauge have that pressure relief valve on it with a clear hose? if so when the car is idleing go ahead and hold that valve and see if the car stalls. if it does you need a pump. you can check the resistance of each wire by ohming from one end to the other of the wire, also check for carbon inside of the spark plug boots or for rust.

 

Pressed the release valve while the car was running, gas flowed fine, so it's not fuel related. I'll check the plugs tomorrow.

[kadeas]

My car does about the same thing. Idles, and runs fine, but if you mash on the gas it misses at about the same RPM, and doesn't want to take off. This only happens while already driving down the road, from a complete stop it takes off fine. If you let off the gas slightly while it's missing it will take off good, almost like it's flooding itself out. Possibly something to do with the shift linkage? Transaxle shift cable out of adjustment? Mine seems to do it when the car wants to drop down into the passing gear. Could it be a prob with our torque converters? I've all but given up on finding the problem. Good luck btw!

[slick]

Update: Swapped in a new VSS, no luck. Tried my extra ecm I had sitting around, no luck either. So now I need to try out tony's extra set of coils and icm.

[kadeas]

Mine's fixed, I cleaned intake, and egr port, and it runs like a top. I think it was the egr port to tell ya the truth.

[5speedz34]

Mine's fixed, I cleaned intake, and egr port, and it runs like a top. I think it was the egr port to tell ya the truth.

 

Why would the EGR stop it from accelerating? It has nothing to do with it.

[kadeas]

Ok, so clean the intake, mine had a bunch of black tarrish stuff stuck to the bottom.

[slick]

Fixed it! ICM was bad. Thanks again Tony!

[4spdz34]

glad to see its fixed. i new it was ignition

[DaveFromColorado]

sorry to bring back an old topic - but my car just (92 Z-34 3.4 DOHC 4T60e) just started doin' the hesitation at 4k, and only a hesitation, seems almost like a limiter at first but once the car makes it past the 4k mark it takes off with some good power, all the wires, plugs, and coils all tested okay (per resistance test while cold) and the injectors ohm'd out just fine too (when I did the intake manifold gasket the other day) when I checked the pressure I tested the flow best I could with the gauage I was using the fuel flowed fine, was idelin' at about 40psi, 45 at WOT, and releasin' the fuel through the pressure releif didn't kill the engine either - I've tried cleanin' the intake and the EGR and still no luck -

 

so I'm askin' - when you replaced the ICM, did you replace the coils as well, or just the ICM - as I want to fix this, but I don't want to spend a pile of money.

 

I've got an ICM off of my old 2.8 Regal - will that work in this car too, or do I need to get one just for the LQ1

 

Thanks in advance!

 

--Dave.

[White93z34]

i believe he just replaced the ICM, his situation was abit different, it just WOULD NOT go past 4k, no matter what, it made driving the most miserable experience

 

no raeason the ICM from the 2.8 won't work.

[slick]

I just replaced the ICM. Coils were fine. The 2.8 ICM will work with no problem, but when you get the chance, pick up one off of a newer 3x00. There supposed to be better.

[5speedz34]

I just replaced the ICM. Coils were fine. The 2.8 ICM will work with no problem, but when you get the chance, pick up one off of a newer 3x00. There supposed to be better.

 

You think so?

 

I thought that was what the problem was with your car was that it had the 3x00 ICM, which isn't good for our cars.

 

So you think that ICM is bad, and its not because its off a 3400. I can take it and get it tested.

[GP1138]

ICM/Coilpacks are pretty much universal with these cars.

 

FWIW: Autozone.com shows the same part number for the 3.4 as for the 3100 for the ICM.

[slick]

Yeah Tony, I think the ICM was just bad.

[DaveFromColorado]

okay, cool, at least I've got a place to start.

 

This was one of the orignial symptoms I was hopin' would go away when I changed my intake manifold gaskets (that and a coolant leak, and a small vacuum leak, and the vacuum line to the FPR was totally shot)

 

I was hopin' it was just a computer re-learn as the car hadn't had a functioning vacuum line to the FPR in who knows how long.

 

I'm gonna try swappin' my ICM's soon, and I'm going to replace the computer too (as I've also got an extra one) because ever since I put this computer into my car, it's acted a bit funny.

 

Thanks again for the pointers -

 

--Dave.

[slick]

You ought to relocate your coilpacks and ICM, just to save the hassle of having to get them out from that akward location.

[JakeMetz63]

my 95 cutty does the same thing

[DaveFromColorado]

so get this.. my power steering line finally went completely out today (dumping all my power steering fluid all over the highway) and the miss went away...

 

I'm sure it's unrelated to the power steering, but it's just creepy that it happened like that.

 

I'm still replacing the ICM and such - I'll probably relocate, but I'm going to get the wires from an other car so I can extend them and keep the same colors.

 

--Dave.