1991 300 I6 2wd EFI HELP!!!
Ok, I bought this truck when I was 17 years old. I came from a long line of non-mechanical people (however with the help of a book I was able to sucessfully replace an automatic transmission on an 83 ranger) so my knowledge is limited, but I want to learn and know if i do enough research I can learn how to do what i need to do with your help.
Ok I bought this truck in 1996 and she ran beautiful. around the spring or summer of 99 I noticed a miss, so i changed the plug and wires which gave me a little improvement, but not a whole bunch. I let it go and for the last 5 or 6 years she has pretty much sat except for out yearly trips to the lake where im hauling camping equipment and a 24' pontoon boat. She still has some power, but she misses like crazy. so this spring due to financial reasons I down to this old truck and it's time I take the abuse I have given her for so long and treat her right. I have a long road ahead of me, but i want to start with the engine.
Let me explain the miss or choke out, not sure which i would call it. it was running so rough it wouldn't stay running in idle. I changed the spark plugs again a few days ago, and the fuel filter. Made a big improvement, but still have problems. when i start it cold I have to rev it up to a higher rpm (not sure what rpm because my guage goes screwy. (it will be sitting at 1000rpm and jump up to 3800rpm without the motor accelerating) Once i rev it for a few seconds it will idle pretty good with an occasional miss maybe one ever 15-25 seconds. not bad at all. As soon as i put it in gear it either stalls out or chokes down to barely running for about 3 seconds and revs up on its own to catch back up to idle speed. (putting it in drive is worse than putting it into reverse for some reason). once i hit the gas to go forward or reverse I have to pump the gas to get it to stay idling. If i were to just step on the gas it would bog down and choke out. It may catch itself and run. once i get going in 1st gear it has a constant miss maybe every second. If i gun it, it seems a bit better to maybe every 2-5 seconds. The big problem is when I hit second gear, or when i try to maintain speed at 55. the truck misses so violently it make the whole truck shake. Once the truck is warmed up i can barely hear a miss and cant feel a miss when i go from stopped to go. However the shifting of gears always bogs it down to barely running where the battery guage drops trying to keep the truck rolling.
Today i took the air filter off and tried to run it. Huge improvement with 1st and 2nd gear, but still missing awfully when trying to maintain speed and still bogging down really low when popping into drive. What do you think my next step is.. distributor? i didnt change the wires. they didnt help last time I changed them so i figure they wouldnt this time.. Oh and last time I changed the plugs was the 1st time i ever did it and when i changed them this time they old ones i put in a long time ago were loose. I'm positive that was what was giving me some performance issues. Oh and I took it to the shop maybe 7 years ago before she sat all the time and they ran some kind of injector test and said all the injectors were doing good, So i'm ruling that out since it was missing before that test was done. so its not injectors, plugs, fuel filter or air filter. all these things (other than injectors have helped improve, but not fix the problem) any suggestions? I also tried to take it to autozone to see if they could give me some codes, but their tool only goes back to 1995. what should i do next?