shawnk007

If im sitting at an idle, my rpms stay constant. They dont jump or fluctuate or anything. But when i push on the gas, my rpms always drop, then they pick up. It does it worse when its cold, and gets a lil better when it warms up, but the issue is still there. If hard on the gas, it will backfire through the intake. It does this in park, neutral or in gear. Throughout the rest of the powerband, everythings fine. My motor is stock with the timing set at 12 degrees. Anyone have this same problem, or have the fix to this?

86_GT_5.0

i would check fuel pressure, correct operation on the coolant temp sensor to the computer, air charge temp sensor, o2s dirty MAF, vaccum leaks just some ideas

shawnk007

I have new 02s. Its speed density. And Im pulling good vacuum. I have a mechanical coolant temp guage, so theres no coolant temp sensor.

mjr46

wrong shawnk007 you have a coolant temp sensor 86 gt is refering to the one for the computer that helps calculate air/fuel mixture on a cold engine if it's sending a wrong temp of coolant to computer it can skew calculations the old addage of garbage in garbage out applies to calculations a computer controlled car makes.

shawnk007

where is this sensor located?

mattdel

to the left of the distributor, screwed into a steel coolant line.

i wrote a tech article about how to test it. check the stickys.

Helmet86

Hey Shawnk007, I have the same problem and I cant figure it out either. I have a 91 5.0 and one thing i notices is that my car runs ten times better when I disconnect my MAF sensor. Till this day I have the problem you have and struggle to keep my car running right. If you find the solution to your problem or any help, let me know. thanks.