I have 83 2.0 spider FI. Just got it about a month ago and it ran ok but had a rough idle especially when cool. I don't remember a hesitation problem at that time.
I changed the aux air valve with a refurbished one and it helped the cold idle tremendously but is still not a great idle.
During driving, I stared to notice a hesitation (mostly when the engine was cold less frequently when warmed up). It is most pronounced at 1st or 2nd gear in the 1500 to 2000 RPM range when I hit the gas: the car hesitates, I let off the gas and try again and eventually we get power. It does not seem to happen as bad at higher RPMs.
The car was almost all original parts when I got it so I decided to take a pit stop and:
replaced the vacuum lines and clamps, fuel lines and clamps, fuel filter, air filter, spark plugs and wires, magnetic pickup, vacuum advance, cleaned the grounds, sent the injectors to be ultra sonic cleaned a got a report back that they are now flowing at the same rate.
Put it all together and the idle is a bit better, cruising is great, but the same hesitation is there if not worst
Here are the theories i can come-up with, does anyone have any ideas:
1- The fuel screen in the gas tank is dirty - (how do i check this?)
2- The timing is off - I put the distributor back in the same position when I changed the vacuum advance but I did not check the timing
3- I guess it could be an air leak
Thanks
. I'm so pumped, i put in a donation in your honor to fiatspider.com.