I have 1988 ford bronco 11-2.9 engine. Tuned last year. only put around 500 miles on it. Only drive 5 miles to work when i drive it. Mostly used for hunting. recently notice after car warms up when I come to a stop car will idle rough very slow and most times will cut off. Local mechanic suggested that fuel injectors may be fouled and put some high price cleaner in gas. I filled tank sunday and have driven about 75 miles and still have noticed no difference. mechanic also says 88 bronco11 does not have an egr valve. Is this correct if not where is it?