Hi

I have a 1994 RX7 and just recently have been having problems with miss fire and rough idle.

When the car is cold there is no problem in starting and running. Driving on the freeway at 65mph ...no problem. However once I hit traffic and the underhood temperature in general reaches the normal extremes, the car starts to idle rough (some time it cuts out due to the low rpm it dips to) and also on overrun it misfires like a pig. I am able to restart the car every time it stalls and if I can get out of the traffic and get up to speed of 65mph the problem disappears after a view miles until the next traffic stop. While in traffic if I keep the revs (2000rpm) up while stopped I can avoid the car from stalling.

I had the car out last Sunday and was running no problem until I hit 130mph for approx 2 - 3 minutes and then I noticed that after coming back down to normal speeds (65mph) the car started missing in forth.

It is obvious that this is a temperature-related problem but I am hoping someone may have come across this.

Is it a spark plug failing under high temperature or the HT leads?

Any help would be appreciated.

Bally

PS the spark plugs and engine I have in the car are only 10k miles old

 

Sorted the problem by changing Spark Plugs (only 9K miles old) and also Spark plug leads.

Bally

 

9k!!! I bet those were some nasty looking plugs!

Damn, I change my plugs every 3k and I use NGK Platinums!

K