92cobra

I have very bad surging when i go above 3k rpms.

I had diagnostics ran and the only thing that came up was the erg valve regulator, i had it replaced, codes were ran again and 12 "cant pass high rpm" came up on his thing. There now saying the next step is to replace the 2 o2 sensors.

Does this seem logical, and will it solve my problem?

92cobra

anyone?

samseed101

I could be wrong, but I don't think that faulty O2 sensors would cause those specific problems.

samseed101

So is the surging not triggering a CEL? Thinking of some possibilities... the electrical component inside the MAF sensorcould be damaged orcontaminated by the impurities in the air.They couldembed themselves to electrical component that senses the air flow causing the sensor to be slightly off, but maybe not enough to trigger a CEL.

Also, how is your fuel pressure when it's surging? Is it possible that you are having pump issues or presure regulators and it's not delievering enough fuel?

Again, I don't think O2 sensors would ahve that effect on older models. I know they can cause issues with the 96+ Mustangs due to their function. But I've never seen anything like that with older cars that only have 2 sensors instead of 4.

luckythirteen13

can you take the car above 3k rpms imidiately after starting the motor?

to see if its the o2's, let the completely cool down. when the motor has been sitting for a few hours, get in the car, start it up and imidiate go down the street and see if you can get the rpms above 3000. the o2's dont send a signal when they are cold. it takes about 30 seconds for them to warm up and send a signal to the computer. if you can go above 3000rpms right after starting the car when the o2s are cold, the you know you have bad o2s. if you still cant get above 3k, then the problem is some where else

vristang

I wouldn't assume that code 12 means there is an issue with the O2's.

From the tone of your post, it sounds like the shop is just running through a list of things that they 'think' will solve an issue.

Have you made an modifications?
what year car?
When did the surging start?


jason

92cobra

its a 1991 mustang gt.

lucky13, i hopped in my car and took her right up to 5grand without hesitation, so im assuming it is bad o2 sensors?

the cel is not on.

92cobra

vristang, ive had the problem ever since i bought the car. I personally havent made any modifications but there is an h pipe, magnaflows or flowmasters i forget and bbk under drive pullies.

92cobra

update, when the car is cold it can easily go up to 5k without hesitation in the least.

mattdel

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