moves slow...

hi there this is first post.nice site.i have two problems with my 1988 caravans.the one i had for six years and now when you started it dont want go very fast.you give it gas but it only will go about forty miles a hour.the other one i just bought and it does the same thing.yesterday i put wires and new plugs but it does the same thing .it will only get up to forty miles a hour.the later i just bought and it was sitting for several years.the first one that i bought sits alot to.they both have the 3.0 engine.the next thing i want to do is check the timming and go from there and mabe change the fuel filter.after that im not sure what to do,thank you for any help...

Welcome to AF! One question, does the engine rev when you press the gas and does not move or does the engine refuse to rev up. If it refuses to rev up then the issues is probably with the catalytic converter. If it revs but does not move then the issue is probably with the transmission. A fuel filter change will not hurt anything and may improve the situation. Post again once you change it to see if the problem goes away or not.

thank you gtp dad for the reply...the vans both run and when its in park it revs up with no problem.when i go and drive them it feels like your pressing on the gas pedal and nothing happens.when you do press on the pedal it builds up to the speed .i ran a code check .you turn the key three times with out starting it and it comes back at this.code 23 throtle body voltage to low.bit thats for single port engines .im not sure what else it means for a 3.0 .the other code it says speed controlled solenoild circut.the other says altenator field not swithes properly.then it went to 55 which means the end,thank you for any help.

You could have a problem with the throttle position sensor. This controls the amount of fuel that the ecm sends to the injectors. This works for all injected engines. Since you have an obd 1 engine it is hard to get specifics on what is actually wrong. I would start with the TPS and I would also check the fuel pressure regulator. If it does not provide enough fuel then the car will be sluggish. Finally, check the speed sensor in the transmission as it can cause similar issues.

thank you gtpdad,i will check those and let you no if helps...so other people can help others who have the same issues.have a nice day