Impreza hesitant on acceleration

[Scuff]

I have a 2wd 1995 impreza with 160,000 miles on it. Well maintaned from previous owner. I just changed the auto transmission with a salvage yard one that had only 55,000 miles on it (a 1994). The problem is that it is hesistant on acceleration and occasionaly makes a "popping" sound while giving it a lot of gas. I checked all the air hoses and they seem to be fine and on correctly. I even cleaned the IAC valve sensor by taking it off and spraying some pb blaster in it to get rid of the minor sludge in there. I have yet to take off the TPS (throttle position sensor and clean that ). ANY IDEAS ON WHY IT IS RELUCTANT TO RUN AT HIGH SPEEDS?

 

Thanks in advance

Any help would be appreciated.

[Andyjo]

dump some sea foam into your pcv valve, clean out the vac system a little maybe? You could also go ahead and add another large grounding cable to the block, from your battery... i've found that my imp. shifts alot nicer now with this mod.

[ninjaben43]

You might have a problem with the MAF (Mass air flow) sensor. Give it a look.

[Scuff]

OK thanks for your help you guys. I did run an additional ground from the battery to the block then to the body. I t seemed to help a little but it still idled and shifted weird. Then i look at the MAF and I wouldnt know if it was broke if it was. Then i talked to a friends husband who is a mechanic and I described what it was doing. He said it sounded like a coil problem. So i took a chance and bought a used coil from a foreign salvage yard . Popped it on in a minute and a half and and drove home with the problem fixed.

 

Thanks

[Andyjo]

which coil? my girlfriend's car is having similar issues sometimes

[Scuff]

The ignition coil. The one where all the spark plug wires go into and mounts on top of the intake manifold with two bolts. If its popping and has zero power up a hill thats probably what it is. It s the last thing i wanted to change but the first thing i should have. Hindsight is 20/20.