1990 Nissan 300ZX Q&A
1990 Nissan 300ZX Question: stumble problems
Need Help any ideas welcome and Thanks ahead of time! Ok I have a 1987 300 zx non turbo, v-6, 5 speed. New oil pump, timing belt, plugs and wires cap button, new head gaskets worked heads intake upper and lower etc. Ok here is the problem it stumbles between 1400 and 2500 near to the point of shutting off. Acts like (A) lack of fuel or and (B) lack of air. Cleaned mass air flow sensor, Checked Belt timing, Checked distributor timing, set at 20 before top dead center, Checked idle set at 700 rpm, Replaced all Vacuum lines, Checked to make sure no vacuum leaks, has 35-45 p.s.i. fuel pressure. Has good exhaust pressure, will idle and rev without stumble but under load as driving stumbles. - lostsoul71
Did you check fuel pressure under load? or idling? - Tomiko
Possible EGR malfunction. Disconnect it and test drive, if the stumble goes away , diagnose the CAUSE of it's improper function , don't just replace the valve , it may not fix the problem. - ziptie12
I've had this problem for several weeks now. Car feels like it has a constant miss throughout the rev range. I have just done a plenum pull, installed new injectors, replaced injector and coil conn...