1991 240 w/redtop, missing badly under boost.

[mzdafrk]

First off I tried searching, and read a lot of posts that covered things i have replaced or checked. thats why I am writing this.

This is my friends car who took it to a shop to have some suspension parts installed, after he picked it up he noticed it was running wierd and died on the way home. Then there was an accident in the family so the car was parked for some time. When He went to drive it again it was running rough. thats when I came in. I looked the car over and found tht the shop, or while it was at the shop, had taken parts off the car. the blow off valve was missing, and a straight pipe was in place. I changed all the fluids, intalled a greddy front mount, new blow off valve, redid all the vacuum lines to proper sources. fixed some minor wiring issues, and found the fuel pump was faulty. replaced the fuel pump with a new walbro, and it started running, but missing like crazy. I thought the turbo may have been damaged during the drive home from the shop, it checked out ok. replaced the coolant temp sensor just as a precaution. Redid the maf wiring, and switched out the coils with a known working set from another car. still missing, installed a new wideband O2 to monitor, all good. Vacuum is good, but has a slight miss under idle. Tripple checked fuel pressure, its good. This has been a frustrating trouble shoot, because it is usually one of the other items that causes the problem. I am open to trying to any idea, but i dont want people to say double check this, tht I already did. What am I missing? It was running good 3 years ago, parts were stolen, and than parked. I know I am overlooking something minor. Oh yeah, compression ois solid on all cylinders.

Thanks in advance.

[ultimateirving]

You didn't mention if you replaced all the fluids and fresh gas after sitting so long. Also how did the plugs look?
Another thing is to actually pressurize the system. If the shop took parts off or they were stolen you don't know for sure if something else is leaking.

[mzdafrk]

sorry, your right. all fluid have been changed out, fresh gas. i installed the front mount to eliminate all the old piping. pressure tested, it held up.

[mzdafrk]

i put new plugs in also.

[Mikester]

^^Understood you changed plugs. How did the old ones look?

You could also try changing the fuel filter because it sat so long.

[di-devol]

Originally Posted by mzdafrk

i put new plugs in also.

What's the gap on the plugs?

[mzdafrk]

i changed the fuel filter, no difference. new plugs are gapped at .028 old plugs didn't look bad. It fires right up, with a intermittent miss. i am ready to yank the whole engine out and redue the swap. its completely frustrating

[ultimateirving]

Pcv or break booster leaking ? Trying to think of not so common leaks or problems, maf housing leaking or rubber intake boot collapsing ?