Problem with Revs?

Question

Hi,Before normal running temp engine runs faultlessly. However, once the temp is normal, pressing on accel pedel causes rpm's to increase for moment of a sec before the revs die off (above 2000rpm not at idle), again for a moment of a second, revs then rise again before falling back off and so on. It is possible sometimes to get past this point but then it just happens again above 4000rpm. Once the engine has cooled again there appears to be no problem, until the temps rise again. Using jumper wire method in diagnostic box has no effect on symptom and no fault codes are logged. If I connect a inductive timing gun to the underbonnet battery feed and the other wire to a ground point and the clamp over one of the plug leads (or even put it near the leads) then the problem goes away as soon as you press the timing trigger. Release the gun trigger and the problem comes back. I changed leads and plugs for new ones today but hasn't changed the problem at all!
please help undriveable. John

Answer 1

take it to a tuner :)

Answer 2

All of that info and you don't say what kind of car you have. Mazda has made a lot of cars, including many with rotary engines. When asking a specific question about a car, let us know what car you have. As for your problem, I think you will need to have a mechanic run some tests on it. Probably an electrical problem.

Answer 3

What year and model is your Mazda. Some emission control devices only operate after the engine is warm. EGR valve can act this way if it is sticking. Common problem in 86 to 90 carb equipped B2000, B2200.

Answer 4

Sounds like you're running way too rich or way too lean. Look at your spark plugs to figure out which one.

Answer 5

geezz write a novel for god sakes lol,,,,,,.....,,, but that is really wierd, is there something wrong with your oil pump maybe, or maybe its has something to do with your cooling system but that should not cause it to rev like that,,, sorry i cant help anymore than that